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Precalculus Skill Builders Vol 1 Solutions

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11. Algebraic Fractions<br />

Facts about Fractions<br />

PK<br />

QK = P Q<br />

where Q ! 0 and K ! 0<br />

Multiplication:<br />

P<br />

Q ! R S = PR<br />

QS<br />

Division:<br />

P<br />

Q ÷ R S = P Q ! S R = PS<br />

QR<br />

Addition:<br />

Subtraction:<br />

P<br />

Q + R Q = P+R<br />

Q<br />

P<br />

Q ! R Q = P!R<br />

Q<br />

Simplify the following fractions.<br />

1.<br />

1 a<br />

b [ 1 ab ] 2.<br />

1 a<br />

1 b [ b a ]<br />

3.<br />

x 2 –9<br />

x–3 [ x + 3 ] 4. x 2 –5x–6<br />

x 2 –1<br />

5.<br />

x 2 –25<br />

5– x<br />

[ !(x + 5) ] 6.<br />

[ x ! 6<br />

x !1 ]<br />

a 3 +b 3<br />

a 2 –b 2 [ a2 ! ab+ b 2<br />

a! b<br />

]<br />

Example:<br />

Solution:<br />

Use Fraction Busters to solve<br />

x<br />

3 + 5 x = 2 .<br />

Multiply every term on both sides of the<br />

equation by all the terms in the<br />

denominator.<br />

Now you have an equation without<br />

fractions.<br />

Use the Quadratic Formula to solve.<br />

3! x ! x 3 + 3! x ! 5 x = 2 ! 3! x<br />

/3! x ! x /3 + 3! /x ! 5 /x = 6x<br />

x 2 + 15 = 6x<br />

x 2 " 6x + 15 = 0<br />

x=3±i 6<br />

<strong>Skill</strong> <strong>Builders</strong>

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