Question

f(x) = x 3 +9x ​2 - 12x -108 find all the zeros of this equation

Answer 1

x^3+9x^2-12x-108
x^2(x + 9) - 12 (x + 9)

(x^2-12)(x + 9)

(x + 2√3)(x – 2√3)(x + 9)
Zeroes of the expression are 

2√3, –2√3 and –9