Simplify the complex rational expression

Question

3/(x+5)+ 6/(x+3) ÷ (3x+13)/(x^2+8x+15)

(please show steps i already know the answer i need to know the steps)

Answer 1

Use the fact that
(x^2+8x+15) = (x+5)(x+3)

Muliply numerator and denominator by that and you will get some big simplifications.

[3(x+3) + 6(x+5)] /(3x +13)
= (9x + 39)/(3x +13)

Do you see another simplication? Factor out "3" in the numerator.