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x\left(x-3\right)+3\left(x+3\right)+x^{2}-12=0
Variable x cannot be equal to any of the values -3,3 since division by zero is not defined. Multiply both sides of the equation by \left(x-3\right)\left(x+3\right).
x^{2}-3x+3\left(x+3\right)+x^{2}-12=0
Use the distributive property to multiply x by x-3.
x^{2}-3x+3x+9+x^{2}-12=0
Use the distributive property to multiply 3 by x+3.
x^{2}+9+x^{2}-12=0
Combine -3x and 3x to get 0.
2x^{2}+9-12=0
Combine x^{2} and x^{2} to get 2x^{2}.
2x^{2}-3=0
Subtract 12 from 9 to get -3.
2x^{2}=3
Add 3 to both sides. Anything plus zero gives itself.
x^{2}=\frac{3}{2}
Divide both sides by 2.
x=\frac{\sqrt{6}}{2} x=-\frac{\sqrt{6}}{2}
Take the square root of both sides of the equation.
x\left(x-3\right)+3\left(x+3\right)+x^{2}-12=0
Variable x cannot be equal to any of the values -3,3 since division by zero is not defined. Multiply both sides of the equation by \left(x-3\right)\left(x+3\right).
x^{2}-3x+3\left(x+3\right)+x^{2}-12=0
Use the distributive property to multiply x by x-3.
x^{2}-3x+3x+9+x^{2}-12=0
Use the distributive property to multiply 3 by x+3.
x^{2}+9+x^{2}-12=0
Combine -3x and 3x to get 0.
2x^{2}+9-12=0
Combine x^{2} and x^{2} to get 2x^{2}.
2x^{2}-3=0
Subtract 12 from 9 to get -3.
x=\frac{0±\sqrt{0^{2}-4\times 2\left(-3\right)}}{2\times 2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 2 for a, 0 for b, and -3 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\times 2\left(-3\right)}}{2\times 2}
Square 0.
x=\frac{0±\sqrt{-8\left(-3\right)}}{2\times 2}
Multiply -4 times 2.
x=\frac{0±\sqrt{24}}{2\times 2}
Multiply -8 times -3.
x=\frac{0±2\sqrt{6}}{2\times 2}
Take the square root of 24.
x=\frac{0±2\sqrt{6}}{4}
Multiply 2 times 2.
x=\frac{\sqrt{6}}{2}
Now solve the equation x=\frac{0±2\sqrt{6}}{4} when ± is plus.
x=-\frac{\sqrt{6}}{2}
Now solve the equation x=\frac{0±2\sqrt{6}}{4} when ± is minus.
x=\frac{\sqrt{6}}{2} x=-\frac{\sqrt{6}}{2}
The equation is now solved.