form a polynomial fx with real coefficients having the given

form a polynomial f(x) with real coefficients having the given degree and zeros
Degree 4 zeros 4+2i 1 multiplicity 2

Solution

Zeroes 4+2i

Imaginay zeroes always occurs in pair

Therefore the other zero is 4-2i

F(x)= (x-4-2i)²(x-4+2i)²

f(x)=x⁴-16x³ + 104x²-320x+400