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108+x^{2}=4x^{2}
Multiply both sides of the equation by 4.
108+x^{2}-4x^{2}=0
Subtract 4x^{2} from both sides.
108-3x^{2}=0
Combine x^{2} and -4x^{2} to get -3x^{2}.
-3x^{2}=-108
Subtract 108 from both sides. Anything subtracted from zero gives its negation.
x^{2}=\frac{-108}{-3}
Divide both sides by -3.
x^{2}=36
Divide -108 by -3 to get 36.
x=6 x=-6
Take the square root of both sides of the equation.
108+x^{2}=4x^{2}
Multiply both sides of the equation by 4.
108+x^{2}-4x^{2}=0
Subtract 4x^{2} from both sides.
108-3x^{2}=0
Combine x^{2} and -4x^{2} to get -3x^{2}.
-3x^{2}+108=0
Quadratic equations like this one, with an x^{2} term but no x term, can still be solved using the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}, once they are put in standard form: ax^{2}+bx+c=0.
x=\frac{0±\sqrt{0^{2}-4\left(-3\right)\times 108}}{2\left(-3\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -3 for a, 0 for b, and 108 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\left(-3\right)\times 108}}{2\left(-3\right)}
Square 0.
x=\frac{0±\sqrt{12\times 108}}{2\left(-3\right)}
Multiply -4 times -3.
x=\frac{0±\sqrt{1296}}{2\left(-3\right)}
Multiply 12 times 108.
x=\frac{0±36}{2\left(-3\right)}
Take the square root of 1296.
x=\frac{0±36}{-6}
Multiply 2 times -3.
x=-6
Now solve the equation x=\frac{0±36}{-6} when ± is plus. Divide 36 by -6.
x=6
Now solve the equation x=\frac{0±36}{-6} when ± is minus. Divide -36 by -6.
x=-6 x=6
The equation is now solved.