Question

Given one zero (solution) of the function, please find the rest. f(x)=x^ 4 -32x^ 2 -144;zero: - 2i

Answer 1

complex roots come in conjugate pairs, so +2i is also a root

x^4 - 32x^2 -144 = (x-2i)(x+2i)*p(x) = (x^2+4)*p(x)
p(x) = x^2 - 36
so the other two roots are 6 and -6