SOLUTION: x^2-4x=1

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Question 691845: x^2-4x=1
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
x%5E2-4x=1

x%5E2-4x-1=0

Use the quadratic formula to solve for x

x+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29

x+=+%28-%28-4%29%2B-sqrt%28%28-4%29%5E2-4%281%29%28-1%29%29%29%2F%282%281%29%29 Plug in a+=+1, b+=+-4, c+=+-1

x+=+%284%2B-sqrt%2816-%28-4%29%29%29%2F%282%29

x+=+%284%2B-sqrt%2816%2B4%29%29%2F%282%29

x+=+%284%2B-sqrt%2820%29%29%2F2

x+=+%284%2Bsqrt%2820%29%29%2F2 or x+=+%284-sqrt%2820%29%29%2F2

x+=+%284%2B2%2Asqrt%285%29%29%2F2 or x+=+%284-2%2Asqrt%285%29%29%2F2

x+=+2%2Bsqrt%285%29 or x+=+2-sqrt%285%29