SOLUTION: Please, help me solved this quadratic equation: x²+12x+36=9

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Question 908430: Please, help me solved this quadratic equation: x²+12x+36=9
Found 2 solutions by Alan3354, richwmiller:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Please, help me solved this quadratic equation: x²+12x+36=9
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Subtract 9 from each side.
x%5E2+%2B+12x+%2B+27+=+0
I would factor it.
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Always get sero (0) on the right side.

Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
x²+12x+27=0
Solved by pluggable solver: Quadratic Formula
Let's use the quadratic formula to solve for x:


Starting with the general quadratic


ax%5E2%2Bbx%2Bc=0


the general solution using the quadratic equation is:


x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29




So lets solve x%5E2%2B12%2Ax%2B27=0 ( notice a=1, b=12, and c=27)





x+=+%28-12+%2B-+sqrt%28+%2812%29%5E2-4%2A1%2A27+%29%29%2F%282%2A1%29 Plug in a=1, b=12, and c=27




x+=+%28-12+%2B-+sqrt%28+144-4%2A1%2A27+%29%29%2F%282%2A1%29 Square 12 to get 144




x+=+%28-12+%2B-+sqrt%28+144%2B-108+%29%29%2F%282%2A1%29 Multiply -4%2A27%2A1 to get -108




x+=+%28-12+%2B-+sqrt%28+36+%29%29%2F%282%2A1%29 Combine like terms in the radicand (everything under the square root)




x+=+%28-12+%2B-+6%29%2F%282%2A1%29 Simplify the square root (note: If you need help with simplifying the square root, check out this solver)




x+=+%28-12+%2B-+6%29%2F2 Multiply 2 and 1 to get 2


So now the expression breaks down into two parts


x+=+%28-12+%2B+6%29%2F2 or x+=+%28-12+-+6%29%2F2


Lets look at the first part:


x=%28-12+%2B+6%29%2F2


x=-6%2F2 Add the terms in the numerator

x=-3 Divide


So one answer is

x=-3




Now lets look at the second part:


x=%28-12+-+6%29%2F2


x=-18%2F2 Subtract the terms in the numerator

x=-9 Divide


So another answer is

x=-9


So our solutions are:

x=-3 or x=-9