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Mathematics LibreTexts

9.9: Exercise Supplement

  • Page ID
    60064
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    Exercise Supplement

    Square Root Expressions - Addition and Subtraction of Square Root Expressions

    For the following problems, simplify the expressions.

    Exercise \(\PageIndex{1}\)

    \(\sqrt{10}\sqrt{2}\)

    Answer

    \(2\sqrt{5}\)

    Exercise \(\PageIndex{2}\)

    \(\sqrt{6}\sqrt{8}\)

    Exercise \(\PageIndex{3}\)

    \(\sqrt{18}\sqrt{40}\)

    Answer

    \(12\sqrt{5}\)

    Exercise \(\PageIndex{4}\)

    \(\sqrt{11}\sqrt{11}\)

    Exercise \(\PageIndex{5}\)

    \(\sqrt{y}\sqrt{y}\)

    Answer

    \(y\)

    Exercise \(\PageIndex{6}\)

    \(\sqrt{r^3}\sqrt{r^3}\)

    Exercise \(\PageIndex{7}\)

    \(\sqrt{m+3}\sqrt{m+3}\)

    Answer

    \(m+3\)

    Exercise \(\PageIndex{8}\)

    \(\sqrt{a-7}\sqrt{a-7}\)

    Exercise \(\PageIndex{9}\)

    \(\sqrt{x^2+4x+4}\)

    Answer

    \(x+2\)

    Exercise \(\PageIndex{10}\)

    \(\sqrt{y^2 - 12y + 36}\)

    Exercise \(\PageIndex{11}\)

    \(\dfrac{\sqrt{x+5}}{\sqrt{x+2}}\)

    Answer

    \(\dfrac{\sqrt{(x+5)(x+2)}}{x+2}\)

    Exercise \(\PageIndex{12}\)

    \(\dfrac{\sqrt{n-3}}{\sqrt{n-1}}\)

    Exercise \(\PageIndex{13}\)

    \(\dfrac{\sqrt{50}}{\sqrt{2}}\)

    Answer

    \(5\)

    Exercise \(\PageIndex{14}\)

    \(\dfrac{\sqrt{75}}{5\sqrt{3}}\)

    Exercise \(\PageIndex{15}\)

    \(\dfrac{\sqrt{a^2 + 6a + 9}}{\sqrt{a + 3}}\)

    Answer

    \(\sqrt{a+3}\)

    Exercise \(\PageIndex{16}\)

    \(\dfrac{\sqrt{4x^2 + 4x + 1}}{\sqrt{2x + 1}}\)

    Exercise \(\PageIndex{17}\)

    \(\dfrac{\sqrt{x^2 - 11x + 24}}{\sqrt{x-8}}\)

    Answer

    \(\sqrt{x-3}\)

    Exercise \(\PageIndex{18}\)

    \(\dfrac{\sqrt{y^2 + 11y + 28}}{\sqrt{y+4}}\)

    Exercise \(\PageIndex{19}\)

    \(\sqrt{3}(\sqrt{5} + \sqrt{3})\)

    Answer

    \(3 + \sqrt{15}\)

    Exercise \(\PageIndex{20}\)

    \(\sqrt{5}(\sqrt{6} - \sqrt{10})\)

    Exercise \(\PageIndex{21}\)

    \(\sqrt{a}(\sqrt{a} - \sqrt{bc})\)

    Answer

    \(a - \sqrt{abc}\)

    Exercise \(\PageIndex{22}\)

    \(\sqrt{x}(\sqrt{x^5} - \sqrt{3x})\)

    Exercise \(\PageIndex{23}\)

    \(\sqrt{7a^3}(\sqrt{2a} - \sqrt{4a^3})\)

    Answer

    \(a^2\sqrt{14} - 2a^3\sqrt{7}\)

    Exercise \(\PageIndex{24}\)

    \(\dfrac{3}{\sqrt{7}}\)

    Exercise \(\PageIndex{25}\)

    \(\dfrac{2}{\sqrt{5}}\)

    Answer

    \(\dfrac{2\sqrt{5}}{5}\)

    Exercise \(\PageIndex{26}\)

    \(\dfrac{6}{\sqrt{2}}\)

    Exercise \(\PageIndex{27}\)

    \(\dfrac{8y}{\sqrt{y}}\)

    Answer

    \(8\sqrt{y}\)

    Exercise \(\PageIndex{28}\)

    \(\dfrac{16a^2}{\sqrt{5a}}\)

    Exercise \(\PageIndex{29}\)

    \((2 + \sqrt{3})(2 - \sqrt{3})\)

    Answer

    \(1\)

    Exercise \(\PageIndex{30}\)

    \((x + \sqrt{8})(3x + \sqrt{8})\)

    Exercise \(\PageIndex{31}\)

    \((4y - \sqrt{3x})(4y + \sqrt{3x})\)

    Answer

    \(16y^2 - 3x\)

    Exercise \(\PageIndex{32}\)

    \((6r + \sqrt{2s})(4r + \sqrt{2s})\)

    Exercise \(\PageIndex{33}\)

    \(\dfrac{2}{2 + \sqrt{7}}\)

    Answer

    \(-\dfrac{2(2- \sqrt{7})}{3}\)

    Exercise \(\PageIndex{34}\)

    \(\dfrac{4}{1 - \sqrt{6}}\)

    Exercise \(\PageIndex{35}\)

    \(\dfrac{6}{x + \sqrt{y}}\)

    Answer

    \(\dfrac{6(x - \sqrt{y})}{x^2 - y}\)

    Exercise \(\PageIndex{36}\)

    \(\dfrac{10}{a - \sqrt{2b}}\)

    Exercise \(\PageIndex{37}\)

    \(\dfrac{\sqrt{5}}{a + \sqrt{3}}\)

    Answer

    \(\dfrac{a\sqrt{5} - \sqrt{15}}{a^2 - 3}\)

    Exercise \(\PageIndex{38}\)

    \(\dfrac{\sqrt{2}}{1 + \sqrt{10}}\)

    Exercise \(\PageIndex{39}\)

    \(\dfrac{8 + \sqrt{3}}{2 + \sqrt{6}}\)

    Answer

    \(\dfrac{8\sqrt{6} - 2\sqrt{3} + 3\sqrt{2} - 16}{2}\)

    Exercise \(\PageIndex{40}\)

    \(\dfrac{4 + \sqrt{11}}{4 - \sqrt{11}}\)

    Exercise \(\PageIndex{41}\)

    \(\sqrt{\dfrac{36a^4b^5c^{11}}{x^2y^5}}\)

    Answer

    \(\dfrac{6a^2b^2c^5\sqrt{bcy}}{xy^3}\)

    Exercise \(\PageIndex{42}\)

    \(\sqrt{x^{12}y^{10}z^8w^7}\)

    Exercise \(\PageIndex{43}\)

    \(\sqrt{32x^5y(x-2)^3}\)

    Answer

    \(4x^2(x-2)\sqrt{2xy(x-2)}\)

    Exercise \(\PageIndex{44}\)

    \(-2\sqrt{60r^4s^3}\)

    Exercise \(\PageIndex{45}\)

    \(\sqrt{\dfrac{3}{16}}\)

    Answer

    \(\dfrac{\sqrt{3}}{4}\)

    Exercise \(\PageIndex{46}\)

    \(\sqrt{\dfrac{4}{25}}\)

    Exercise \(\PageIndex{47}\)

    \(\sqrt{\dfrac{9}{16}}\)

    Answer

    \(\dfrac{3}{4}\)

    Exercise \(\PageIndex{48}\)

    \(\sqrt{\dfrac{5}{36}}\)

    Exercise \(\PageIndex{49}\)

    \(\sqrt{\dfrac{1}{6}}\)

    Answer

    \(\dfrac{\sqrt{6}}{6}\)

    Exercise \(\PageIndex{50}\)

    \(\sqrt{\dfrac{3}{10}}\)

    Exercise \(\PageIndex{51}\)

    \(\sqrt{(x+4)^4(x-1)^5}\)

    Answer

    \((x+4)^2(x-1)^2(\sqrt{x-1})\)

    Exercise \(\PageIndex{52}\)

    \(\sqrt{(3x + 5)^3(2x - 7)^3}\)

    Exercise \(\PageIndex{53}\)

    \(\sqrt{(y-3z)^{12}(y+3z)^{10}(y-5z)^3}\)

    Answer

    \((y-3z)^6(y+3z)^5(y-5z)\sqrt{y-5z}\)

    Exercise \(\PageIndex{54}\)

    \(\sqrt{(8a-5b)^{26}(2a - 9b)^{40}(a-b)^{15}}\)

    Exercise \(\PageIndex{55}\)

    \(4\sqrt{11} + 8\sqrt{11}\)

    Answer

    \(12\sqrt{11}\)

    Exercise \(\PageIndex{56}\)

    \(-\sqrt{6} + 5\sqrt{6}\)

    Exercise \(\PageIndex{57}\)

    \(5\sqrt{60} - 7\sqrt{15}\)

    Answer

    \(3\sqrt{15}\)

    Exercise \(\PageIndex{58}\)

    \(4ax^2\sqrt{75x^4} + 6a\sqrt{3x^8}\)

    Exercise \(\PageIndex{59}\)

    \(-3\sqrt{54} - 16\sqrt{96}\)

    Answer

    \(-73\sqrt{6}\)

    Exercise \(\PageIndex{60}\)

    \(\sqrt{18x^2y}\sqrt{2x^2y}\)

    Exercise \(\PageIndex{61}\)

    \(\sqrt{4x^2+32x+64} + \sqrt{10x^2+80x+160}\)

    Answer

    \((2 + \sqrt{10})(x + 4)\)

    Exercise \(\PageIndex{62}\)

    \(-2\sqrt{9x^2 - 42x + 49} + 5\sqrt{18x^2 - 84x + 98}\)

    Exercise \(\PageIndex{63}\)

    \(-10\sqrt{56a^3b^7} + 2a^2b\sqrt{126ab^5}\)

    Answer

    \((-20ab^3 + 6a^2b^3)\sqrt{14ab}\)

    Exercise \(\PageIndex{64}\)

    \(\dfrac{\sqrt{3x} - \sqrt{5x}}{\sqrt{7x} + \sqrt{2x}}\)

    Exercise \(\PageIndex{65}\)

    \(\dfrac{\sqrt{6a} + \sqrt{2a}}{\sqrt{3a} - \sqrt{5a}}\)

    Answer

    \(\dfrac{-3\sqrt{2} - \sqrt{30} - \sqrt{6} - \sqrt{10}}{2}\)

    Square Root Equations with Applications

    For the following problems, solve the equations.

    Exercise \(\PageIndex{66}\)

    \(\sqrt{3x} = 9\)

    Exercise \(\PageIndex{67}\)

    \(\sqrt{4a} = 16\)

    Answer

    \(a = 64\)

    Exercise \(\PageIndex{68}\)

    \(\sqrt{x} + 7 = 4\)

    Exercise \(\PageIndex{69}\)

    \(\sqrt{a + 6} = -5\)

    Answer

    No Solution

    Exercise \(\PageIndex{70}\)

    \(\sqrt{4a + 5} = 21\)

    Exercise \(\PageIndex{71}\)

    \(\sqrt{3m + 7} = 10\)

    Answer

    \(m = 31\)

    Exercise \(\PageIndex{72}\)

    \(\sqrt{y + 10} = 5\)

    Exercise \(\PageIndex{73}\)

    \(\sqrt{a - 7} = 6\)

    Answer

    \(a = 43\)

    Exercise \(\PageIndex{74}\)

    \(\sqrt{4x - 8} = x - 2\)

    Exercise \(\PageIndex{75}\)

    \(\sqrt{2x + 3} + 8 =11\)

    Answer

    \(x=3\)

    Exercise \(\PageIndex{76}\)

    \(\sqrt{a^2 + 5} + 5 = a\)

    Exercise \(\PageIndex{77}\)

    \(\sqrt{5b + 4} - 5 = -2\)

    Answer

    \(b = 1\)

    Exercise \(\PageIndex{78}\)

    \(\sqrt{2a + 1} - 10 = -3\)

    Exercise \(\PageIndex{79}\)

    \(\sqrt{2x + 5} = \sqrt{x + 3}\)

    Answer

    \(x = -2\)

    Exercise \(\PageIndex{80}\)

    \(\sqrt{5a - 11}\)

    Exercise \(\PageIndex{81}\)

    At a small business, the monthly number of sales \(S\) is approximately related to the number of employees \(E\) by \(S = 140 + 8\sqrt{E - 2}\)

    a) Determine the approximate number of sales if the number of employees is \(27\).

    b) Determine the approximate number of employees if the monthly sales are 268.

    Answer

    a) \(S = 180\)

    b) \(E = 258\)

    Exercise \(\PageIndex{82}\)

    The resonance frequency \(f\) in an electronic circuit containing inductance \(L\) and capacitance \(C\) in series is given by:

    \(f = \dfrac{1}{2\pi\sqrt{LC}}\)

    a) Determine the resonance frequency in an electronic circuit if the inductance is \(9\) and the capacitance is \(0.0001\). Use \(\pi = 3.14\).

    b) Determine the inductance in an electric circuit if the resonance frequency is \(5.308\) and the capacitance is \(0.0001\). Use \(\pi = 3.14\).

    Exercise \(\PageIndex{83}\)

    If two magnetic poles of strength \(m\) and \(m'\) are at a distance \(r\) centimeters (cm) apart, the force \9F\) of repulsion in air between them is given by:

    \(F = \dfrac{mm'}{r^2}\)

    a) Determine the force of repulsion if two magnetic poles of strengths 22 and 46 units are 8 cm apart.

    b) Determine how far apart are two magnetic poles of strengths 14 and 16 units if the force of repulsion in air between them is 42 units.

    Answer

    a) \(F=15.8125\)  

    b) \(r=12.31\) cm


    This page titled 9.9: Exercise Supplement is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by Denny Burzynski & Wade Ellis, Jr. (OpenStax CNX) .

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