Question

Find the zeros of the polynomial function.

f(x) = x^3 + 4x^2 - 9x - 36

Answer 1

hmmm...........
x^3 + 4x^2 - 9x - 36

= ( x -3) [ x^2 + 7x + 12 ]

= ( x -3 ) [ x^2 + 4x + 3x + 12 ]

= ( x - 3 ) [ x ( x + 4) + 3(x + 4 ) ]

= ( x -3 ) [ (x + 3) ( x +4) ]

make them equal to zero..
x= 3 or x = -3 or x = -2
which means
the zeros r
3 , -3 , 4