SOLUTION: Solve for X 45. 2x^2 + 8x - 3 = 0

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Question 171820: Solve for X
45. 2x^2 + 8x - 3 = 0
Answer by jim_thompson5910(28715) About Me  (Show Source):
You can put this solution on YOUR website!

2x%5E2%2B8x-3=0 Start with the given equation.


Notice we have a quadratic equation in the form of ax%5E2%2Bbx%2Bc where a=2, b=8, and c=-3


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-%288%29+%2B-+sqrt%28+%288%29%5E2-4%282%29%28-3%29+%29%29%2F%282%282%29%29 Plug in a=2, b=8, and c=-3


x+=+%28-8+%2B-+sqrt%28+64-4%282%29%28-3%29+%29%29%2F%282%282%29%29 Square 8 to get 64.


x+=+%28-8+%2B-+sqrt%28+64--24+%29%29%2F%282%282%29%29 Multiply 4%282%29%28-3%29 to get -24


x+=+%28-8+%2B-+sqrt%28+64%2B24+%29%29%2F%282%282%29%29 Rewrite sqrt%2864--24%29 as sqrt%2864%2B24%29


x+=+%28-8+%2B-+sqrt%28+88+%29%29%2F%282%282%29%29 Add 64 to 24 to get 88


x+=+%28-8+%2B-+sqrt%28+88+%29%29%2F%284%29 Multiply 2 and 2 to get 4.


x+=+%28-8+%2B-+2%2Asqrt%2822%29%29%2F%284%29 Simplify the square root (note: If you need help with simplifying square roots, check out this solver)


x+=+%28-8%2B2%2Asqrt%2822%29%29%2F%284%29 or x+=+%28-8-2%2Asqrt%2822%29%29%2F%284%29 Break up the expression.


So the answers are x+=+%28-8%2B2%2Asqrt%2822%29%29%2F%284%29 or x+=+%28-8-2%2Asqrt%2822%29%29%2F%284%29


which approximate to x=0.345 or x=-4.345