We know if x=a is a zero of a polynomial and then x-a is a factor of f(x). Since 2 and -2 are zeros of f(x) Therefore: (x-2) (x+2) = x²-4 (x²-4) is a factor of f(x) Now, we divide 2x⁴-5x³-11x²+20x+12 by g(x)=(x²-4) to find the zero f(x). By using division algorithm we have, f(x)=g(x)×q(x)-r(x) 2x⁴-5x³-11x²+20x+12=(x²-4)(2x²-5x-3) = (x-2)(x+2)[2x(x-3)+1(x-3)] =(x-2)(x+2)(x-3)(2x+1) Hence the zeros of the polynomial are; 2,-2,3,-1/2