SOLUTION: Can someone please help with the following: x^2 - 8x + 5 = 0

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Question 275246: Can someone please help with the following:
x^2 - 8x + 5 = 0
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

x%5E2-8x%2B5=0 Start with the given equation.


Notice that the quadratic x%5E2-8x%2B5 is in the form of Ax%5E2%2BBx%2BC where A=1, B=-8, and C=5


Let's use the quadratic formula to solve for "x":


x+=+%28-B+%2B-+sqrt%28+B%5E2-4AC+%29%29%2F%282A%29 Start with the quadratic formula


x+=+%28-%28-8%29+%2B-+sqrt%28+%28-8%29%5E2-4%281%29%285%29+%29%29%2F%282%281%29%29 Plug in A=1, B=-8, and C=5


x+=+%288+%2B-+sqrt%28+%28-8%29%5E2-4%281%29%285%29+%29%29%2F%282%281%29%29 Negate -8 to get 8.


x+=+%288+%2B-+sqrt%28+64-4%281%29%285%29+%29%29%2F%282%281%29%29 Square -8 to get 64.


x+=+%288+%2B-+sqrt%28+64-20+%29%29%2F%282%281%29%29 Multiply 4%281%29%285%29 to get 20


x+=+%288+%2B-+sqrt%28+44+%29%29%2F%282%281%29%29 Subtract 20 from 64 to get 44


x+=+%288+%2B-+sqrt%28+44+%29%29%2F%282%29 Multiply 2 and 1 to get 2.


x+=+%288+%2B-+2%2Asqrt%2811%29%29%2F%282%29 Simplify the square root (note: If you need help with simplifying square roots, check out this solver)


x+=+%288%29%2F%282%29+%2B-+%282%2Asqrt%2811%29%29%2F%282%29 Break up the fraction.


x+=+4+%2B-+sqrt%2811%29 Reduce.


x+=+4%2Bsqrt%2811%29 or x+=+4-sqrt%2811%29 Break up the expression.


So the solutions are x+=+4%2Bsqrt%2811%29 or x+=+4-sqrt%2811%29