Question

Which quadratic equation has the roots -1+4i and -1-4i

A. X^2+2x+2=0
B. 2x^2+x+17=0
C. X^2+2x+17=0
D. 2x^2+x+2=0

Answer 1

C

Explanation:

Solve the quadratic in answer choice C using the quadratic formula:

`x=(-b+/-√(b^2-4ac) )/(2a)`.

Here a=1, b=2, and c=17.

Substitute and you'll have:

`x=(-b+/-√(b^2-4ac) )/(2a) =(-2+/-√((-2)^2-4(1)(17)) )/(2(1))=(-2+/-√(4-68))/(2))`

`(-2+/-√(-64) )/(2)=(-2+/-8i )/(2)=-1+/- 4i`