Question

If f(x)=4x^3+16x^2-23x-15 and f(−5)=0, then find all of the zeros of f(x) algebraically.

Answer 1

4x^3+16x^2-23x-15 = (x+5)×(x+1/2)×(x-1.5)

so zeroes are at: -5, -1/2, and 1.5