SOLUTION: {{{x^2+8x-1=0}}}

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Question 204502: x%5E2%2B8x-1=0
Answer by alicealc(293) About Me  (Show Source):
You can put this solution on YOUR website!
because it can't be factorized, we can use this formula:
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%28-8+%2B-+sqrt%288%5E2-4%2A1%2A%28-1%29%29%29%2F%282%2A1%29+
x+=+%28-8+%2B-+sqrt%2816%2B4%29%29%2F%282%29
x+=+%28-8+%2B-+sqrt%2820%29%29%2F%282%29
x+=+%28-8+%2B-+sqrt%284%2A5%29%29%2F%282%29
x+=+%28-8+%2B-+2%2Asqrt%285%29%29%2F%282%29+
x+=+%28-4+%2B-+sqrt%285%29%29
so,
x1 = -4+%2B+sqrt%285%29
x2 = -4+-+sqrt%285%29