Simplify $ \dfrac{x^3 + 15x^2 + 75x + 125}{x^2 – 25} (x – 5)$.
Options
a) x2 + 5x + 25
b) x2 – 25
c) x2 + 10x + 25
d) x2 + 25
Solution
As per question
$ \dfrac{x^3 + 15x^2 + 75x + 125}{x^2 – 25} (x – 5)$
$ \dfrac{x^3 + 15x^2 + 75x + 125 (x – 5)}{(x – 5)(x + 5)}$
$ \dfrac{(x +5)^2 (x + 5)}{x + 5}$
(x + 5)2 = x2 + 10x + 25
Ans is ) x2 + 10x + 25