Question

What is the difference?

Answer 1

Answer:

D. $\frac{x^{2}+3x-12 }{(x-5)(x+3)(x+7)}$ or StartFraction x squared + 3 x minus 12 Over (x + 3) (x minus 5) (x + 7) EndFraction

Step-by-step explanation:

Given the expression $\frac{x}{x^{2}-2x-15 } - \frac{4}{x^{2} + 2x - 35 }$, the dfference is expressed as follows;

Step1: First we need to factorize the denominator of each function.

$\frac{x}{x^{2}-2x-15 } - \frac{4}{x^{2} + 2x - 35 }\\= \frac{x}{x^{2}-5x+3x-15 } - \frac{4}{x^{2} + 7x-5x - 35 }\\= \frac{x}{x(x-5)+3(x-5) } - \frac{4}{x( x+ 7)x-5(x +7) }\\= \frac{x}{(x-5)(x+3) } - \frac{4}{(x-5)(x +7) }$

Step 2: We will find the LCM of the resulting expression

$= \frac{x}{(x-5)(x+3) } - \frac{4}{(x-5)(x +7) }\\= \frac{x(x+7)-4(x+3)}{(x-5)(x+3)(x+7)} \\= \frac{x^{2}+7x-4x-12 }{(x-5)(x+3)(x+7)} \\= \frac{x^{2}+3x-12 }{(x-5)(x+3)(x+7)}$

The final expression gives the difference