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Mathematics LibreTexts

14.5E: Exercises

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Practice Makes Perfect

Exercise 14.5E.19 Use Pascal's Triangle to Expand a Binomial

In the following exercises, expand each binomial using Pascal’s Triangle.

  1. (x+y)4
  2. (a+b)8
  3. (m+n)10
  4. (p+q)9
  5. (xy)5
  6. (ab)6
  7. (x+4)4
  8. (x+5)3
  9. (y+2)5
  10. (y+1)7
  11. (z3)5
  12. (z2)6
  13. (4x1)3
  14. (3x1)5
  15. (3x4)4
  16. (3x5)3
  17. (2x+3y)3
  18. (3x+5y)3
Answer

2. a8+8a7b+28a6b2+56a5b3+70a4b4+56a3b5+28a2b6+8ab7+b8

4. p9+9p8q+36p7q2+84p6q3+126p5q4+126p4q5+84p3q6+36p2q7+9pq8+q9

6. a66a5b+15a4b220a3b3+15a2b46ab5+b6

8. x3+15x2+75x+125

10. y7+7y6+21y5+35y4+35y3+21y2+7y+1

12. z612z5+60z4160z3+240z2192z+64

14. 243x5405x4+270x390x2+15x1

16. 27x3135x2+225x125

18. 27x3+135x2y+225xy2+125y3

Exercise 14.5E.20 Evaluate a Binomial Coefficient
    1. (81)
    2. (1010)
    3. (60)
    4. (93)
    1. (71)
    2. (44)
    3. (30)
    4. (53)
    1. (31)
    2. (99)
    3. (70)
    4. (53)
    1. (41)
    2. (55)
    3. (80)
    4. (119)
Answer

2.

  1. 7
  2. 1
  3. 1
  4. 45

4.

  1. 4
  2. 1
  3. 1
  4. 55
Exercise 14.5E.21 Use the Binomial Theorem to Expand a Binomial

In the following exercises, expand each binomial.

  1. (x+y)3
  2. (m+n)5
  3. (a+b)6
  4. (s+t)7
  5. (x2)4
  6. (y3)4
  7. (p1)5
  8. (q4)3
  9. (3xy)5
  10. (5x2y)4
  11. (2x+5y)4
  12. (3x+4y)5
Answer

2. m5+5m4n+10m3n2+10m2n3+5mn4+n5

4. s7+7s6t+21s5t2+35s4t3+35s3t4+21s2t5+7st6+t7

6. y412y3+54y2108y+81

8. q312q2+48q64

10. 625x41000x3y+600x2y2160xy3+16y4

12. 243x5+1620x4y+4320x3y2+5760x2y3+3840xy4+1024y5

Exercise 14.5E.22 Use the Binomial Theorem to Expand a Binomial

In the following exercises, find the indicated term in the expansion of the binomial.

  1. Sixth term of (x+y)10
  2. Fifth term of (a+b)9
  3. Fourth term of (xy)8
  4. Seventh term of (xy)11
Answer

2. 126a5b4

4. 462x5y6

Exercise 14.5E.23 Use the Binomial Theorem to Expand a Binomial

In the following exercises, find the coefficient of the indicated term in the expansion of the binomial.

  1. y3 term of (y+5)4
  2. x6 term of (x+2)8
  3. x5 term of (x4)6
  4. x7 term of (x3)9
  5. a4b2 term of (2a+b)6
  6. p5q4 term of (3p+q)9
Answer

2. 112

4. 324

6. 30,618

Exercise 14.5E.24 Writing Exercises
  1. In your own words explain how to find the rows of the Pascal's Triangle. Write the first five rows of Pascal's Triangle.
  2. In your own words, explain the pattern of exponents for each variable in the expansion of.
  3. In your own words, explain the difference between (a+b)n and (ab)n.
  4. In your own words, explain how to find a specific term in the expansion of a binomial without expanding the whole thing. Use an example to help explain.
Answer

2. Answers will vary

4. Answers will vary

Self Check

a. After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section.

This figure shows a table with four rows and four columns. The first row is the header row and reads. “I can”, “Confidently”, “With some help” and “No, I don’t get it”. The first column, beginning at the second row reads, “Use Pascal’s Triangle to Expand a Binomial”, “Evaluate a Binomial Coefficient” and “Use the Binomial Theorem to Expand a Binomial”. The remaining columns are blank.
Figure 12.4.31

b. On a scale of 1-10, how would you rate your mastery of this section in light of your responses on the checklist? How can you improve this?


This page titled 14.5E: Exercises is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by Chau D Tran.

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