SOLUTION: x^2-8x-4=0 ?? solve each equation by completing the square, thank you for the help I really need it.

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Question 642216: x^2-8x-4=0 ??
solve each equation by completing the square, thank you for the help I really need it.
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
x%5E2-8x-4=0
x%5E2-8x+=+4
take half 'b', square it, and add to both sides:
x%5E2-8x%2B16+=+4%2B16
%28x-4%29%28x-4%29+=+20
%28x-4%29%5E2+=+20
take the square root of both sides:
%28x-4%29+=+sqrt%2820%29
x-4+=+sqrt%282%2A2%2A5%29
x-4+=+2%2Asqrt%285%29
x+=+2%2Asqrt%285%29%2B4
so x can be two possibilities:
x+=+2%2Asqrt%285%29%2B4
and
x+=+-2%2Asqrt%285%29%2B4
.
or approximately,
x = {-0.47, 8.47}