SOLUTION: I need help to figure out the x. the problem is {{{4x^2+3x-8=0}}}

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Question 238656: I need help to figure out the x. the problem is 4x%5E2%2B3x-8=0
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

4x%5E2%2B3x-8=0 Start with the given equation.


Notice that the quadratic 4x%5E2%2B3x-8 is in the form of Ax%5E2%2BBx%2BC where A=4, B=3, and C=-8


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%284%29%28-8%29+%29%29%2F%282%284%29%29 Plug in A=4, B=3, and C=-8


x+=+%28-3+%2B-+sqrt%28+9-4%284%29%28-8%29+%29%29%2F%282%284%29%29 Square 3 to get 9.


x+=+%28-3+%2B-+sqrt%28+9--128+%29%29%2F%282%284%29%29 Multiply 4%284%29%28-8%29 to get -128


x+=+%28-3+%2B-+sqrt%28+9%2B128+%29%29%2F%282%284%29%29 Rewrite sqrt%289--128%29 as sqrt%289%2B128%29


x+=+%28-3+%2B-+sqrt%28+137+%29%29%2F%282%284%29%29 Add 9 to 128 to get 137


x+=+%28-3+%2B-+sqrt%28+137+%29%29%2F%288%29 Multiply 2 and 4 to get 8.


x+=+%28-3%2Bsqrt%28137%29%29%2F%288%29 or x+=+%28-3-sqrt%28137%29%29%2F%288%29 Break up the expression.


So the solutions are x+=+%28-3%2Bsqrt%28137%29%29%2F%288%29 or x+=+%28-3-sqrt%28137%29%29%2F%288%29


which approximate to x=1.088 or x=-1.838