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2x^{2}=72
Multiply x and x to get x^{2}.
x^{2}=\frac{72}{2}
Divide both sides by 2.
x^{2}=36
Divide 72 by 2 to get 36.
x=6 x=-6
Take the square root of both sides of the equation.
2x^{2}=72
Multiply x and x to get x^{2}.
2x^{2}-72=0
Subtract 72 from both sides.
x=\frac{0±\sqrt{0^{2}-4\times 2\left(-72\right)}}{2\times 2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 2 for a, 0 for b, and -72 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\times 2\left(-72\right)}}{2\times 2}
Square 0.
x=\frac{0±\sqrt{-8\left(-72\right)}}{2\times 2}
Multiply -4 times 2.
x=\frac{0±\sqrt{576}}{2\times 2}
Multiply -8 times -72.
x=\frac{0±24}{2\times 2}
Take the square root of 576.
x=\frac{0±24}{4}
Multiply 2 times 2.
x=6
Now solve the equation x=\frac{0±24}{4} when ± is plus. Divide 24 by 4.
x=-6
Now solve the equation x=\frac{0±24}{4} when ± is minus. Divide -24 by 4.
x=6 x=-6
The equation is now solved.