Let f(x)=x3+2x2−11x−12Given : −1 is a zero of the polynomial , which means (x+1) is a factor of f(x) Dividing f(x) by (x+1) we getf(x) becomes:f(x)=(x+1)(x2+x−12)=(x+1)(x2+4x−3x−12)=(x+1)(x−3)(x−4)if f(x)=0⇒(x+1)(x−3)(x+4)=0either (x+1)=0 or (x−3)=0  or (x+4)=0x=−1 or x=3 or x=−4zeros of the polynomial are −1, 3 and −4