SOLUTION: x^2+3x+8=5

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Question 568741: x^2+3x+8=5
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

x%5E2%2B3x%2B8=5 Start with the given equation.


x%5E2%2B3x%2B8-5=0 Subtract 5 from both sides.


x%5E2%2B3x%2B3=0 Combine like terms.


Notice that the quadratic x%5E2%2B3x%2B3 is in the form of Ax%5E2%2BBx%2BC where A=1, B=3, 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-%283%29+%2B-+sqrt%28+%283%29%5E2-4%281%29%283%29+%29%29%2F%282%281%29%29 Plug in A=1, B=3, and C=3


x+=+%28-3+%2B-+sqrt%28+9-4%281%29%283%29+%29%29%2F%282%281%29%29 Square 3 to get 9.


x+=+%28-3+%2B-+sqrt%28+9-12+%29%29%2F%282%281%29%29 Multiply 4%281%29%283%29 to get 12


x+=+%28-3+%2B-+sqrt%28+-3+%29%29%2F%282%281%29%29 Subtract 12 from 9 to get -3


x+=+%28-3+%2B-+sqrt%28+-3+%29%29%2F%282%29 Multiply 2 and 1 to get 2.


x+=+%28-3+%2B-+i%2Asqrt%283%29%29%2F%282%29 Simplify the square root (note: If you need help with simplifying square roots, check out this solver)


x+=+%28-3%2Bi%2Asqrt%283%29%29%2F%282%29 or x+=+%28-3-i%2Asqrt%283%29%29%2F%282%29 Break up the expression.


So the solutions are x+=+%28-3%2Bi%2Asqrt%283%29%29%2F%282%29 or x+=+%28-3-i%2Asqrt%283%29%29%2F%282%29

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