SOLUTION: Solve 2x^-7x-2=0

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Question 187590: Solve
2x^-7x-2=0
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
I'm assuming that the equation is really 2x%5E2-7x-2=0


2x%5E2-7x-2=0 Start with the given equation.


Notice we have a quadratic equation in the form of ax%5E2%2Bbx%2Bc where a=2, b=-7, and c=-2


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-%28-7%29+%2B-+sqrt%28+%28-7%29%5E2-4%282%29%28-2%29+%29%29%2F%282%282%29%29 Plug in a=2, b=-7, and c=-2


x+=+%287+%2B-+sqrt%28+%28-7%29%5E2-4%282%29%28-2%29+%29%29%2F%282%282%29%29 Negate -7 to get 7.


x+=+%287+%2B-+sqrt%28+49-4%282%29%28-2%29+%29%29%2F%282%282%29%29 Square -7 to get 49.


x+=+%287+%2B-+sqrt%28+49--16+%29%29%2F%282%282%29%29 Multiply 4%282%29%28-2%29 to get -16


x+=+%287+%2B-+sqrt%28+49%2B16+%29%29%2F%282%282%29%29 Rewrite sqrt%2849--16%29 as sqrt%2849%2B16%29


x+=+%287+%2B-+sqrt%28+65+%29%29%2F%282%282%29%29 Add 49 to 16 to get 65


x+=+%287+%2B-+sqrt%28+65+%29%29%2F%284%29 Multiply 2 and 2 to get 4.


x+=+%287%2Bsqrt%2865%29%29%2F%284%29 or x+=+%287-sqrt%2865%29%29%2F%284%29 Break up the expression.


So the answers are x+=+%287%2Bsqrt%2865%29%29%2F%284%29 or x+=+%287-sqrt%2865%29%29%2F%284%29