Solve for x
x=20
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x^{2}-14x+49=\left(2x-3\right)^{2}-3x^{2}
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(x-7\right)^{2}.
x^{2}-14x+49=4x^{2}-12x+9-3x^{2}
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(2x-3\right)^{2}.
x^{2}-14x+49=x^{2}-12x+9
Combine 4x^{2} and -3x^{2} to get x^{2}.
x^{2}-14x+49-x^{2}=-12x+9
Subtract x^{2} from both sides.
-14x+49=-12x+9
Combine x^{2} and -x^{2} to get 0.
-14x+49+12x=9
Add 12x to both sides.
-2x+49=9
Combine -14x and 12x to get -2x.
-2x=9-49
Subtract 49 from both sides.
-2x=-40
Subtract 49 from 9 to get -40.
x=\frac{-40}{-2}
Divide both sides by -2.
x=20
Divide -40 by -2 to get 20.
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