Skip to main content
Mathematics LibreTexts

13.1.7: Chapter 7

  • Page ID
    117742
  • \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)

    \( \newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\)

    ( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\)

    \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

    \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\)

    \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

    \( \newcommand{\Span}{\mathrm{span}}\)

    \( \newcommand{\id}{\mathrm{id}}\)

    \( \newcommand{\Span}{\mathrm{span}}\)

    \( \newcommand{\kernel}{\mathrm{null}\,}\)

    \( \newcommand{\range}{\mathrm{range}\,}\)

    \( \newcommand{\RealPart}{\mathrm{Re}}\)

    \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

    \( \newcommand{\Argument}{\mathrm{Arg}}\)

    \( \newcommand{\norm}[1]{\| #1 \|}\)

    \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

    \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\AA}{\unicode[.8,0]{x212B}}\)

    \( \newcommand{\vectorA}[1]{\vec{#1}}      % arrow\)

    \( \newcommand{\vectorAt}[1]{\vec{\text{#1}}}      % arrow\)

    \( \newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vectorC}[1]{\textbf{#1}} \)

    \( \newcommand{\vectorD}[1]{\overrightarrow{#1}} \)

    \( \newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}} \)

    \( \newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}} \)

    \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)

    \(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)

    Be Prepared

    6y6y

    425425

    154154

    37303730

    27x−323627x−3236

    8x+268x+26

    2323

    154154

    x=4x=4

    x=−1x=−1

    n=9,n=−4n=9,n=−4

    y=10−5x2y=10−5x2

    n=−2n=-2

    The speed of the bus is 28 mph.

    x=107x=107

    ⓐ 1; ⓑ −8; ⓒ 0

    x>−2x>−2

    [−3,5)[−3,5)

    Try It

    ⓐ x=0x=0 ⓑ n=−13n=−13
    ⓒ a=−1,a=−3a=−1,a=−3

    ⓐ q=0q=0 ⓑ y=−23y=−23
    ⓒ m=2,m=−3m=2,m=−3

    x+1x−1,x+1x−1, x≠2,x≠2, x≠1x≠1

    x−5x−1,x−5x−1, x≠−2,x≠−2, x≠1x≠1

    2(x−3y)3(x+3y)2(x−3y)3(x+3y)

    5(x−y)2(x+5y)5(x−y)2(x+5y)

    −x+1x+5−x+1x+5

    −x+2x+1−x+2x+1

    x−22(x+3)x−22(x+3)

    3(x−6)x+53(x−6)x+5

    x−4x−5x−4x−5

    −(b+2)(b−1)(1+b)(b+4)−(b+2)(b−1)(1+b)(b+4)

    2(x2+2x+4)(x+2)(x2−2x+4)2(x2+2x+4)(x+2)(x2−2x+4)

    2zz−12zz−1

    x+24x+24

    2y+52y+5

    2(m+1)(m+2)3(m+4)(m−3)2(m+1)(m+2)3(m+4)(m−3)

    (n+5)(n+9)2(n+6)(2n+3)(n+5)(n+9)2(n+6)(2n+3)

    The domain of R(x)R(x) is all real numbers where x≠5x≠5 and x≠−1.x≠−1.

    The domain of R(x)R(x) is all real numbers where x≠4x≠4 and x≠−2.x≠−2.

    R(x)=2R(x)=2

    R(x)=13R(x)=13

    R(x)=x−24(x−8)R(x)=x−24(x−8)

    R(x)=x(x−2)x−1R(x)=x(x−2)x−1

    x+2x+2

    x+3x+3

    x−11x−2x−11x−2

    x−3x+9x−3x+9

    y+3y+2y+3y+2

    3n−2n−13n−2n−1

    ⓐ (x−4)(x+3)(x+4)(x−4)(x+3)(x+4)
    ⓑ 2x+8(x−4)(x+3)(x+4)2x+8(x−4)(x+3)(x+4),
    x+3(x−4)(x+3)(x+4)x+3(x−4)(x+3)(x+4)

    ⓐ (x+2)(x−5)(x+1)(x+2)(x−5)(x+1)
    ⓑ 3x2+3x(x+2)(x−5)(x+1)3x2+3x(x+2)(x−5)(x+1),
    5x−25(x+2)(x−5)(x+1)5x−25(x+2)(x−5)(x+1)

    7x−4(x−2)(x+3)7x−4(x−2)(x+3)

    7m+25(m+3)(m+4)7m+25(m+3)(m+4)

    5m2−9m+2(m+1)(m−2)(m+2)5m2−9m+2(m+1)(m−2)(m+2)

    2n2+12n−30(n+2)(n−5)(n+3)2n2+12n−30(n+2)(n−5)(n+3)

    1x−21x−2

    −3z−3−3z−3

    5x+1(x−6)(x+1)5x+1(x−6)(x+1)

    y+3y+4y+3y+4

    1(b+1)(b−1)1(b+1)(b−1)

    1(x+2)(x+1)1(x+2)(x+1)

    v+3v+1v+3v+1

    3ww+73ww+7

    x−7x−4x−7x−4

    x2−3x+18(x+3)(x−3)x2−3x+18(x+3)(x−3)

    23(x−1)23(x−1)

    12(x−3)12(x−3)

    14111411

    10231023

    y+xy−xy+xy−x

    abb−aabb−a

    b(b+2)(b−5)3b−5b(b+2)(b−5)3b−5

    3c+33c+3

    7373

    103103

    b+aa2+b2b+aa2+b2

    y−xxyy−xxy

    3(x−2)5x+73(x−2)5x+7

    x+216x−43x+216x−43

    35x+2235x+22

    2(2y2+13y+5)3y2(2y2+13y+5)3y

    xx+4xx+4

    x(x+1)3(x−1)x(x+1)3(x−1)

    y=−157y=−157

    x=1513x=1513

    x=−3,x=5x=−3,x=5

    y=−2,y=6y=−2,y=6

    x=23x=23

    y=2y=2

    There is no solution.

    There is no solution.

    x=3x=3

    y=7y=7

    There is no solution.

    There is no solution.

    There is no solution.

    There is no solution.

    ⓐ The domain is all real numbers except x≠3x≠3 and x≠4.x≠4. ⓑ x=2,x=143x=2,x=143
    ⓒ (2,3),(143,3)(2,3),(143,3)

    ⓐ The domain is all real numbers except x≠1x≠1 and x≠5.x≠5. ⓑ x=214x=214 ⓒ (214,4)(214,4)

    y=mx−4m+5y=mx−4m+5

    y=mx+5m+1y=mx+5m+1

    a=bcb−1a=bcb−1

    y=3xx+6y=3xx+6

    y=33y=33

    z=14z=14

    The pediatrician will prescribe 12 ml of acetaminophen to Emilia.

    The pediatrician will prescribe 180 mg of fever reducer to Isabella.

    The distance is 150 miles.

    The distance is 350 miles.

    The telephone pole is 40 feet tall.

    The pine tree is 60 feet tall.

    Link’s biking speed is 15 mph.

    The speed of Danica’s boat is 17 mph.

    Dennis’s uphill speed was 5 mph and his downhill speed was 10 mph.

    Joon’s rate on the country roads was 50 mph.

    Kayla’s biking speed was 15 mph.

    Victoria jogged 6 mph on the flat trail.

    When the two gardeners work together it takes 2 hours and 24 minutes.

    When Daria and her mother work together it takes 2 hours and 6 minutes.

    Kristina can paint the room in 12 hours.

    It will take Jordan 6 hours.

    ⓐ c=4.8tc=4.8t ⓑ He would burn 432 calories.

    ⓐ d=50td=50t ⓑ It would travel 250 miles.

    ⓐ h=130th=130t ⓑ 123123 hours

    ⓐ x=3500px=3500p ⓑ 500 units

    (−∞,−4)∪[2,∞)(−∞,−4)∪[2,∞)

    (−∞,−2]∪(4,∞)(−∞,−2]∪(4,∞)

    (−32,3)(−32,3)

    (−8,4)(−8,4)

    (−∞,−4)∪(2,∞)(−∞,−4)∪(2,∞)

    (−∞,−4)∪(3,∞)(−∞,−4)∪(3,∞)

    (2,4)(2,4)

    (3,6)(3,6)

    (−4,2](−4,2]

    [−1,4)[−1,4)

    ⓐ c(x)=20x+6000xc(x)=20x+6000x
    ⓑ More than 150 items must be produced to keep the average cost below $60 per item.

    ⓐ c(x)=5x+900xc(x)=5x+900x ⓑ More than 60 items must be produced to keep the average cost below $20 per item.

    Section 7.1 Exercises

    1.

    ⓐ z=0z=0 ⓑ p=56p=56
    ⓒ n=−4,n=2n=−4,n=2

    3.

    ⓐ y=0y=0, ⓑ x=−12x=−12, ⓒ u=−4,u=7u=−4,u=7

    5.

    −45−45

    7.

    2m23n2m23n

    9.

    83(n≠2)83(n≠2)

    11.

    x+5x−1x+5x−1

    13.

    a+2a+8a+2a+8

    15.

    p2+4p−2p2+4p−2

    17.

    4b(b−4)(b+5)(b−8)4b(b−4)(b+5)(b−8)

    19.

    3(m+5n)4(m−5n)3(m+5n)4(m−5n)

    21.

    −1−1

    23.

    −5y+4−5y+4

    25.

    w2−6w+36w−6w2−6w+36w−6

    27.

    −z−54+z−z−54+z

    29.

    310310

    31.

    x38yx38y

    33.

    p(p−4)2(p−9)p(p−4)2(p−9)

    35.

    y−53(y+5)y−53(y+5)

    37.

    −4(b+9)3(b+7)−4(b+9)3(b+7)

    39.

    (3c−1)(c+5)(3c+1)(c−5)(3c−1)(c+5)(3c+1)(c−5)

    41.

    −(m−2)(m−3)(3+m)(m+4)−(m−2)(m−3)(3+m)(m+4)

    43.

    −1v+5−1v+5

    45.

    3ss+43ss+4

    47.

    4(p2−pq+q2)(p−q)(p2+pq+q2)4(p2−pq+q2)(p−q)(p2+pq+q2)

    49.

    x−28x(x+5)x−28x(x+5)

    51.

    2a−752a−75

    53.

    3(3c−5)3(3c−5)

    55.

    4(m+8)(m+7)3(m−4)(m+2)4(m+8)(m+7)3(m−4)(m+2)

    57.

    (4p+1)(p−4)3p(p+9)(p−1)(4p+1)(p−4)3p(p+9)(p−1)

    59.

    x≠5x≠5 and x≠−5x≠−5

    61.

    x≠2x≠2 and x≠−3x≠−3

    63.

    R(x)=2R(x)=2

    65.

    R(x)=x+52x(x+2)R(x)=x+52x(x+2)

    67.

    R(x)=3x(x+7)x−7R(x)=3x(x+7)x−7

    69.

    R(x)=x(x−5)x−6R(x)=x(x−5)x−6

    71.

    Answers will vary.

    73.

    Answers will vary.

    Section 7.2 Exercises

    75.

    3535

    77.

    3c+54c−53c+54c−5

    79.

    r+8r+8

    81.

    2ww−42ww−4

    83.

    3a+73a+7

    85.

    m−22m−22

    87.

    p+3p+5p+3p+5

    89.

    r+9r+7r+9r+7

    91.

    44

    93.

    x+2x+2

    95.

    z+4z−5z+4z−5

    97.

    4b−3b−74b−3b−7

    99.

    ⓐ (x+2)(x−4)(x+3)(x+2)(x−4)(x+3)
    ⓑ 5x+15(x+2)(x−4)(x+3)5x+15(x+2)(x−4)(x+3),
    2x2+4x(x+2)(x−4)(x+3)2x2+4x(x+2)(x−4)(x+3)

    101.

    ⓐ (z−2)(z+4)(z+2)(z−2)(z+4)(z+2)
    ⓑ 9z+18(z−2)(z+4)(z+2)9z+18(z−2)(z+4)(z+2),
    4z2+16z(z−2)(z+4)(z+2)4z2+16z(z−2)(z+4)(z+2)

    103.

    ⓐ (b+3)(b+3)(b−5)(b+3)(b+3)(b−5)
    ⓑ 4b−20(b+3)(b+3)(b−5)4b−20(b+3)(b+3)(b−5),
    2b2+6b(b+3)(b+3)(b−5)2b2+6b(b+3)(b+3)(b−5)

    105.

    ⓐ (d+5)(3d−1)(d−6)(d+5)(3d−1)(d−6)
    ⓑ 2d−12(d+5)(3d−1)(d−6)2d−12(d+5)(3d−1)(d−6),
    5d2+25d(d+5)(3d−1)(d−6)5d2+25d(d+5)(3d−1)(d−6)

    107.

    21y+8x30x2y221y+8x30x2y2

    109.

    5r−7(r+4)(r−5)5r−7(r+4)(r−5)

    111.

    11w+1(3w−2)(w+1)11w+1(3w−2)(w+1)

    113.

    2y2+y+9(y+3)(y−1)2y2+y+9(y+3)(y−1)

    115.

    b(5b+10+2a2)a2(b−2)(b+2)b(5b+10+2a2)a2(b−2)(b+2)

    117.

    −mm+4−mm+4

    119.

    3(r2+6r+18)(r+1)(r+6)(r+3)3(r2+6r+18)(r+1)(r+6)(r+3)

    121.

    2(7t−6)(t−6)(t+6)2(7t−6)(t−6)(t+6)

    123.

    4a2+25a−6(a+3)(a+6)4a2+25a−6(a+3)(a+6)

    125.

    −6m−6−6m−6

    127.

    p+2p+3p+2p+3

    129.

    3r−23r−2

    131.

    4(8x+1)10x−14(8x+1)10x−1

    133.

    x−5(x−4)(x+1)(x−1)x−5(x−4)(x+1)(x−1)

    135.

    1(x−1)(x+1)1(x−1)(x+1)

    137.

    5a2+7a−36a(a−2)5a2+7a−36a(a−2)

    139.

    c−5c+2c−5c+2

    141.

    3(d+1)d+23(d+1)d+2

    143.

    ⓐ R(x)=−(x+8)(x+1)(x−2)(x+3)R(x)=−(x+8)(x+1)(x−2)(x+3) ⓑ R(x)=x+1x+3R(x)=x+1x+3

    145.

    ⓐ 3(3x+8)(x−8)(x+8)3(3x+8)(x−8)(x+8)
    ⓑ R(x)=3x+8R(x)=3x+8

    147.

    Answers will vary.

    149.

    ⓐ Answers will vary.
    ⓑ Answers will vary.
    ⓒ Answers will vary.
    ⓓ x+yxyx+yxy

    Section 7.3 Exercises

    151.

    a−42aa−42a

    153.

    12(c−2)12(c−2)

    155.

    12131213

    157.

    20572057

    159.

    n2+mm−n2n2+mm−n2

    161.

    rtt−rrtt−r

    163.

    (x+1)(x−3)2(x+1)(x−3)2

    165.

    4a+14a+1

    167.

    118118

    169.

    1919

    171.

    c2+cc−d2c2+cc−d2

    173.

    pqq−ppqq−p

    175.

    2x−103x+162x−103x+16

    177.

    3z−193z+83z−193z+8

    179.

    43a−743a−7

    181.

    2c+295c2c+295c

    183.

    2p−552p−55

    185.

    m(m−5)(4m−19)(m+5)m(m−5)(4m−19)(m+5)

    187.

    13241324

    189.

    2(a−4)2(a−4)

    191.

    3mnn−m3mnn−m

    193.

    (x−1)(x−2)6(x−1)(x−2)6

    195.

    Answers will vary.

    Section 7.4 Exercises

    197.

    a=10a=10

    199.

    v=4021v=4021

    201.

    m=−2,m=4m=−2,m=4

    203.

    p=−5,p=−4p=−5,p=−4

    205.

    v=14v=14

    207.

    x=−45x=−45

    209.

    z=−145z=−145

    211.

    q=−18,q=−1q=−18,q=−1

    213.

    no solutionno solution

    215.

    no solutionno solution

    217.

    b=−8b=−8

    219.

    d=2d=2

    221.

    n=1n=1

    223.

    no solutionno solution

    225.

    s=54s=54

    227.

    x=−43x=−43

    229.

    no solution

    231.

    ⓐ The domain is all real numbers except x≠−2x≠−2 and x≠−4.x≠−4. ⓑ x=−3,x=−145x=−3,x=−145 ⓒ (−3,5),(−145,5)(−3,5),(−145,5)

    233.

    ⓐ The domain is all real numbers except x≠2x≠2 and x≠5.x≠5. ⓑ x=92,x=92, ⓒ (92,2)(92,2)

    235.

    r=C2πr=C2π

    237.

    w=2v+7w=2v+7

    239.

    c=b+3+2aac=b+3+2aa

    241.

    p=q4q−2p=q4q−2

    243.

    w=15v10+vw=15v10+v

    245.

    n=5m+234n=5m+234

    247.

    c=Em2c=Em2

    249.

    y=20x12−xy=20x12−x

    251.

    Answers will vary.

    Section 7.5 Exercises

    253.

    x=49x=49

    255.

    p=−11p=−11

    257.

    a=16a=16

    259.

    m=60m=60

    261.

    p=30p=30

    263.

    ⓐ 162 beats per minute ⓑ yes

    265.

    99 ml

    267.

    159159 calories

    269.

    325325 Canadian dollars

    271.

    33 cups

    273.

    4 bags

    275.

    ⓐ 6 ⓑ 1212

    277.

    950 miles

    279.

    680 miles

    281.

    2323 foot (88 in.)

    283.

    247.3247.3 feet

    285.

    160160 mph

    287.

    2929 mph

    289.

    3030 mph

    291.

    2020 mph

    293.

    44 mph

    295.

    6060 mph

    297.

    650650 mph

    299.

    5050 mph

    301.

    5050 mph

    303.

    3 mph

    305.

    22 hours

    307.

    22 hours and 4444 minutes

    309.

    77 hours and 3030 minutes

    311.

    1010 min

    313.

    y=143xy=143x

    315.

    p=3.2qp=3.2q

    317.

    ⓐ P=2.5gP=2.5g ⓑ $82.50$82.50

    319.

    ⓐ m=8vm=8v ⓑ 1616 liters

    321.

    ⓐ L=3d2L=3d2 ⓑ 300300 pounds

    323.

    y=20xy=20x

    325.

    v=3wv=3w

    327.

    ⓐ g=92,400wg=92,400w ⓑ 16.8 mpg

    329.

    ⓐ t=1000rt=1000r ⓑ 2.52.5 hours

    331.

    ⓐ c=2tc=2t ⓑ 11 cavity

    333.

    ⓐ c=2.5mc=2.5m ⓑ $55

    335.

    Answers will vary.

    337.

    Answers will vary.

    Section 7.6 Exercises

    339.

    (−∞,−4)∪[3,∞)(−∞,−4)∪[3,∞)

    341.

    [−1,3)[−1,3)

    343.

    (−∞,1)∪(7,∞)(−∞,1)∪(7,∞)

    345.

    (−5,6)(−5,6)

    347.

    (−52,5)(−52,5)

    349.

    (−∞,−3)∪(6,∞)(−∞,−3)∪(6,∞)

    351.

    [−9,6)[−9,6)

    353.

    (−∞,−6]∪(4,∞)(−∞,−6]∪(4,∞)

    355.

    (−∞,−4)∪(−3,∞)(−∞,−4)∪(−3,∞)

    357.

    (1,4)(1,4)

    359.

    (−∞,−3)∪(52,∞)(−∞,−3)∪(52,∞)

    361.

    (−∞,23)∪(32,∞)(−∞,23)∪(32,∞)

    363.

    (−∞,0)∪(0,4)∪(6,∞)(−∞,0)∪(0,4)∪(6,∞)

    365.

    [−2,0)∪(0,4][−2,0)∪(0,4]

    367.

    (−4,4)(−4,4)

    369.

    [−10,−1)∪(2,∞)[−10,−1)∪(2,∞)

    371.

    (2,5](2,5]

    373.

    (−2,6](−2,6]

    375.

    Answers will vary.

    Review Exercises

    377.

    a≠23a≠23

    379.

    y≠0y≠0

    381.

    3434

    383.

    x+3x+4x+3x+4

    385.

    1616

    387.

    −3x2−3x2

    389.

    3x(x+6)(x+6)3x(x+6)(x+6)

    391.

    −111−w−111−w

    393.

    5c+45c+4

    395.

    R(x)=3R(x)=3

    397.

    11

    399.

    y+5y+5

    401.

    x+4x+4

    403.

    q2−2q−3(q+5)(q+1)q2-2q-3(q+5)(q+1)

    405.

    15w+26w−115w+26w−1

    407.

    3b2+19b−16b2−493b2+19b−16b2−49

    409.

    (a+2)(a−5)(a+4)(a+2)(a−5)(a+4)

    411.

    (3p−1)(p+6)(p+8)(3p−1)(p+6)(p+8)

    413.

    11c−12(c−2)(c+3)11c−12(c−2)(c+3)

    415.

    5x2+26x(x+4)(x+4)(x+6)5x2+26x(x+4)(x+4)(x+6)

    417.

    2(y2+10y−2)(y+2)(y+8)2(y2+10y−2)(y+2)(y+8)

    419.

    2m−7m+22m−7m+2

    421.

    4a−84a−8

    423.

    R(x)=x+8x+5R(x)=x+8x+5

    425.

    R(x)=2x+11R(x)=2x+11

    427.

    x−22xx−22x

    429.

    (x+2)(x−5)2(x+2)(x−5)2

    431.

    118118

    433.

    z−521z+21z−521z+21

    435.

    x=67x=67

    437.

    b=32b=32

    439.

    no solution

    441.

    ⓐ The domain is all real numbers except x≠2x≠2 and x≠4.x≠4. ⓑ x=1,x=6x=1,x=6
    ⓒ (1,1),(6,1)(1,1),(6,1)

    443.

    l=Vhwl=Vhw

    445.

    z=y+5+7xxz=y+5+7xx

    447.

    x=125x=125

    449.

    s=15s=15

    451.

    11261126 calories

    453.

    b=9;x=213b=9;x=213

    455.

    23 feet

    457.

    4545 mph

    459.

    1616 mph

    461.

    4848 minutes

    463.

    1212 days

    465.

    x=7x=7

    467.

    301301 mph

    469.

    288288 feet

    471.

    99 tickets

    473.

    (−4,3](−4,3]

    475.

    [−6,4)[−6,4)

    477.

    (−∞,−2]∪[4,∞)(−∞,−2]∪[4,∞)

    479.

    (−∞,2)∪[5,∞)(−∞,2)∪[5,∞)

    481.

    ⓐ c(x)=150x+100000xc(x)=150x+100000x
    ⓑ More than 10,000 items must be produced to keep the average cost below $160$160 per item.

    Practice Test

    483.

    a3ba3b

    485.

    x+33xx+33x

    487.

    x−3x+9x−3x+9

    489.

    3n−2n−13n−2n−1

    491.

    n−mm+nn−mm+n

    493.

    z=12z=12

    495.

    [−3,6)[−3,6)

    497.

    (−∞,0)∪(0,4]∪[6,∞)(−∞,0)∪(0,4]∪[6,∞)

    499.

    R(x)=1(x+2)(x+2)R(x)=1(x+2)(x+2)

    501.

    (−3,52)(−3,52)

    503.

    y=8116y=8116

    505.

    Oliver’s dad would take 445445 hours to split the logs himself.

    507.

    The distance between Dayton and Columbus is 64 miles.


    13.1.7: Chapter 7 is shared under a not declared license and was authored, remixed, and/or curated by LibreTexts.

    • Was this article helpful?