SOLUTION: 2x^2 + 3x -1 = 0

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Question 481217: 2x^2 + 3x -1 = 0
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

2x%5E2%2B3x-1=0 Start with the given equation.


Notice that the quadratic 2x%5E2%2B3x-1 is in the form of Ax%5E2%2BBx%2BC where A=2, B=3, and C=-1


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-%283%29+%2B-+sqrt%28+%283%29%5E2-4%282%29%28-1%29+%29%29%2F%282%282%29%29 Plug in A=2, B=3, and C=-1


x+=+%28-3+%2B-+sqrt%28+9-4%282%29%28-1%29+%29%29%2F%282%282%29%29 Square 3 to get 9.


x+=+%28-3+%2B-+sqrt%28+9--8+%29%29%2F%282%282%29%29 Multiply 4%282%29%28-1%29 to get -8


x+=+%28-3+%2B-+sqrt%28+9%2B8+%29%29%2F%282%282%29%29 Rewrite sqrt%289--8%29 as sqrt%289%2B8%29


x+=+%28-3+%2B-+sqrt%28+17+%29%29%2F%282%282%29%29 Add 9 to 8 to get 17


x+=+%28-3+%2B-+sqrt%28+17+%29%29%2F%284%29 Multiply 2 and 2 to get 4.


x+=+%28-3%2Bsqrt%2817%29%29%2F%284%29 or x+=+%28-3-sqrt%2817%29%29%2F%284%29 Break up the expression.


So the solutions are x+=+%28-3%2Bsqrt%2817%29%29%2F%284%29 or x+=+%28-3-sqrt%2817%29%29%2F%284%29