Polynomial with real coefficients always has even number of complex roots. We know that one of them is 2 + 5i so the second one will be 2 - 5i and:

$f(x)=\big(x-4\big)\big(x-(-8)\big)\big(x-(2+5i)\big)\big(x-(2-5i)\big)=\\\\=(x-4)(x+8)(x-2-5i)(x-2+5i)=\\\\=(x^2-4x+8x-32)(x^2-2x+5ix-2x+4-10i-5ix+10i-25i^2)\\\\=\big(x^2+4x-32\big)\big(x^2-4x+4-25\cdot(-1)\big)=\\\\=(x^2+4x-32)(x^2-4x+29)=\\\\=x^4-4x^3+29x^2+4x^3-16x^2+116x-32x^2+128x-928=\\\\=\boxed{x^4-19x^2+244x-928}$

Answer B.

8 0

3 years ago

Read 2 more answers

Why is 6/8 greater than 5/8 but less than 7/8 I need to explain

Alona [7]

On the number line, 1 2 3 4 5 6 7 8 9, 6 is in between 5 and 7.

4 0

2 years ago

Could someone help me with this please !

likoan [24]

List of prime numbers: 2,3,5,7,11

Both C and D equal 2 which is a prime number.