Question

Using the given zero, find all other zeros of f(x).

-2i is a zero of f(x) = x4 - 45x2 - 196

Answer 1

so +2i will also be a zero of f(x)

Answer 2

2i is one of the other zero as complex zeros of a real polynomial always come in conjugate pairs. Complex conjugate of a+bi is a-bi.

Answer 3

so is it 2i,7,-7??

Answer 4

Because 2i is a zero and -2i is a zero, the f(x) is divisible \((x-2i)(x+2i)=x^2+4\). Divide f(x) by \(x^2+4\) to yield a quadratic. Solve that quadratic.