How do you write a polynomial with zeros 4, 4, 2+i and leading coefficient 1?

1 Answer
Feb 18, 2017

P(x)=x^4-12x^3+53x^2-104x+80P(x)=x412x3+53x2104x+80

Explanation:

4,4,2+i4,4,2+i
Root 44 is multiplicity 22
2+i2+i Complex Conjugate Zero is 2-i2i, we have:
P(x)=(x-4)^2(x-2-i)(x-2+i)P(x)=(x4)2(x2i)(x2+i)
P(x)=(x^2-8x+16)[(x-2)^2-i^2]P(x)=(x28x+16)[(x2)2i2]
P(x)=(x^2-8x+16)(x^2-4x+4-(-1)]P(x)=(x28x+16)(x24x+4(1)]
P(x)=(x^2-8x+16)(x^2-4x+5)P(x)=(x28x+16)(x24x+5)
P(x)=x^4-4x^3+5x^2-8x^3+32x^2-40x+16x^2-64x+80P(x)=x44x3+5x28x3+32x240x+16x264x+80
P(x)=x^4-12x^3+53x^2-104x+80P(x)=x412x3+53x2104x+80