Question

12) Add the fractions, and simplify if possible. (y+7)/(y^2-y-12) - 2/(y^2-9)

Answer 1

Answer:

$\dfrac{y^2+2y-13}{(y-4)(y+3)(y-3)}$

Step-by-step explanation:

Given the expression

$\dfrac{y+7}{y^2-y-12}-\dfrac{2}{y^2-9}$

First, factor each denominator:

1. $y^2-y-12=y^2-4y+3y-12=y(y-4)+3(y-4)=(y-4)(y+3)$

2. $y^2-9=(y-3)(y+3)$

Now the expression is

$\dfrac{y+7}{(y-4)(y+3)}-\dfrac{2}{(y-3)(y+3)}$

Now, multiply the first numerator by (y-3) and the second by (y-4) and write the result as a fraction with denominator $(y-4)(y+3)(y-3):$

$\dfrac{(y+7)(y-3)-2(y-4)}{(y-4)(y+3)(y-3)}=\dfrac{y^2-3y+7y-21-2y+8}{(y-4)(y+3)(y-3)}=\dfrac{y^2+2y-13}{(y-4)(y+3)(y-3)}$

This fraction cannot be simplified more.