Solve for x
x=-1
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x^{2}+12x+36=\left(x-4\right)^{2}
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(x+6\right)^{2}.
x^{2}+12x+36=x^{2}-8x+16
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(x-4\right)^{2}.
x^{2}+12x+36-x^{2}=-8x+16
Subtract x^{2} from both sides.
12x+36=-8x+16
Combine x^{2} and -x^{2} to get 0.
12x+36+8x=16
Add 8x to both sides.
20x+36=16
Combine 12x and 8x to get 20x.
20x=16-36
Subtract 36 from both sides.
20x=-20
Subtract 36 from 16 to get -20.
x=\frac{-20}{20}
Divide both sides by 20.
x=-1
Divide -20 by 20 to get -1.
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