Question

X2 + 4x + 8 = 0

Select one:
A. {0, -4}
B. {2 ± 2i}
C. {-2 ± 2}
D. {-2 ± 2i}

Answer 1

Explanation:

I'm assuming you're factoring this! I will throw the values into the quadratic formula:

`x=(-4+/-√(4^2-4(1)(8)) )/(2)` which simplifies to

`x=\frac{-4+/-√(-16) }{}`

Everybody knows that you can't have a negative under a radical that has an even index, so we have to offset it with an i-squared:

`x=\frac{-4+/-√(i^2(16)) }{}` which simplifies to

`x=(-4+/-4i)/(2)` which simplifies, finally, to

x = -2 ± 2i

Choice D.