SOLUTION: x(x-4)=-8 What do I do when there is a negative under the square root? Do I use i for imaginary number?

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Question 61508: x(x-4)=-8
What do I do when there is a negative under the square root? Do I use i for imaginary number?
Answer by funmath(2933) About Me  (Show Source):
You can put this solution on YOUR website!
Yes, sqrt%28-1%29=i.
:
x(x-4)=-8
x%5E2-4x=-8
x%5E2-4x%2B8=-8%2B8
x%5E2-4x%2B8=0
a=1, b=-4, and c=8
The quadratic formula is:
highlight%28x=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29%29
x=%28-%28-4%29%2B-sqrt%28%28-4%29%5E2-4%281%29%288%29%29%29%2F%282%281%29%29
x=%284%2B-sqrt%2816-32%29%29%2F2
x=%284%2B-sqrt%28-16%29%29%2F2
x=%284-4i%29%2F2 and x=%284%2B4i%29%2F2
x=4%2F2-4i%2F2 and x=4%2F2%2B4i%2F2
x=2-2i and x=2%2B2i
Happy Calculating!!!