If 4 - 2i is a zero of a polynomial equation, what is another zero?

Zahra was given two data sets, one without an outlier and one with an outlier. data without an outlier: 15, 19, 22, 26, 29 data with an outlier: 15, 19, 22, 26, 29, 81

In trapezoid efgh, m∠hef=(4x2+16)∘ and m∠gfe=(5x2+12)∘. find the value of x so that efgh is isosceles.

Can someone me with this problem i don't understand i need