Solve for x
x=-2
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x^{2}-6x+9=\left(x+7\right)^{2}
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(x-3\right)^{2}.
x^{2}-6x+9=x^{2}+14x+49
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(x+7\right)^{2}.
x^{2}-6x+9-x^{2}=14x+49
Subtract x^{2} from both sides.
-6x+9=14x+49
Combine x^{2} and -x^{2} to get 0.
-6x+9-14x=49
Subtract 14x from both sides.
-20x+9=49
Combine -6x and -14x to get -20x.
-20x=49-9
Subtract 9 from both sides.
-20x=40
Subtract 9 from 49 to get 40.
x=\frac{40}{-20}
Divide both sides by -20.
x=-2
Divide 40 by -20 to get -2.
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