find all the zeros of f(x)=x3-3x2+4x-12

Answer 1

you know that are all factors of 12. A little regrouping shows you have

f(x) = x^3-3x^2+4x-12
= x^2(x-3) + 4(x-3)
= (x^2+4)(x-3)

so, f(x) = 0 at x = 3, ±2i