SOLUTION: x squared - 16 times x - 64 equals 0 i need to solve it

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Question 626499: x squared - 16 times x - 64 equals 0

i need to solve it
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

x%5E2-16x%2B64=0 Start with the given equation.


Notice that the quadratic x%5E2-16x%2B64 is in the form of Ax%5E2%2BBx%2BC where A=1, B=-16, and C=64


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-%28-16%29+%2B-+sqrt%28+%28-16%29%5E2-4%281%29%2864%29+%29%29%2F%282%281%29%29 Plug in A=1, B=-16, and C=64


x+=+%2816+%2B-+sqrt%28+%28-16%29%5E2-4%281%29%2864%29+%29%29%2F%282%281%29%29 Negate -16 to get 16.


x+=+%2816+%2B-+sqrt%28+256-4%281%29%2864%29+%29%29%2F%282%281%29%29 Square -16 to get 256.


x+=+%2816+%2B-+sqrt%28+256-256+%29%29%2F%282%281%29%29 Multiply 4%281%29%2864%29 to get 256


x+=+%2816+%2B-+sqrt%28+0+%29%29%2F%282%281%29%29 Subtract 256 from 256 to get 0


x+=+%2816+%2B-+sqrt%28+0+%29%29%2F%282%29 Multiply 2 and 1 to get 2.


x+=+%2816+%2B-+0%29%2F%282%29 Take the square root of 0 to get 0.


x+=+%2816+%2B+0%29%2F%282%29 or x+=+%2816+-+0%29%2F%282%29 Break up the expression.


x+=+%2816%29%2F%282%29 or x+=++%2816%29%2F%282%29 Combine like terms.


x+=+8 or x+=+8 Simplify.


So the only solution is x+=+8


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