Question

Find a degree 3 polynomial with real coefficients having zeros 1 and 2-2i and a lead coefficient of 1. Write P in expanded form. Be sure to write the full equation, including P(x)=.

Answer 1

Answer:

Step-by-step explanation:

complex roots always occur in pairs.

roots are 1,2-2i,2+2i

P(x)=a(x-a)(x-b)(x-c)

P(x)=1(x-1)[x-(2-2i)][x-(2+2i)]

=1(x-1)[(x-2)+2i][(x-2)-2i]

=(x-1)[(x-2)²-(2i)²]

=(x-1)[(x-2)²-4i²]

=(x-1)[x²-4x+4-4(-1)]

=(x-1)[x²-4x+4+4]

=(x-1)[x²-4x+8]

=x³-4x²+8x-x²+4x-8

=x³-5x²+12x-8