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9=x^{2}\times \frac{1}{16}
Calculate the square root of 256 and get 16.
x^{2}\times \frac{1}{16}=9
Swap sides so that all variable terms are on the left hand side.
x^{2}\times \frac{1}{16}-9=0
Subtract 9 from both sides.
x^{2}-144=0
Multiply both sides by 16.
\left(x-12\right)\left(x+12\right)=0
Consider x^{2}-144. Rewrite x^{2}-144 as x^{2}-12^{2}. The difference of squares can be factored using the rule: a^{2}-b^{2}=\left(a-b\right)\left(a+b\right).
x=12 x=-12
To find equation solutions, solve x-12=0 and x+12=0.
9=x^{2}\times \frac{1}{16}
Calculate the square root of 256 and get 16.
x^{2}\times \frac{1}{16}=9
Swap sides so that all variable terms are on the left hand side.
x^{2}=9\times 16
Multiply both sides by 16, the reciprocal of \frac{1}{16}.
x^{2}=144
Multiply 9 and 16 to get 144.
x=12 x=-12
Take the square root of both sides of the equation.
9=x^{2}\times \frac{1}{16}
Calculate the square root of 256 and get 16.
x^{2}\times \frac{1}{16}=9
Swap sides so that all variable terms are on the left hand side.
x^{2}\times \frac{1}{16}-9=0
Subtract 9 from both sides.
\frac{1}{16}x^{2}-9=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\times \frac{1}{16}\left(-9\right)}}{2\times \frac{1}{16}}
This equation is in standard form: ax^{2}+bx+c=0. Substitute \frac{1}{16} for a, 0 for b, and -9 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\times \frac{1}{16}\left(-9\right)}}{2\times \frac{1}{16}}
Square 0.
x=\frac{0±\sqrt{-\frac{1}{4}\left(-9\right)}}{2\times \frac{1}{16}}
Multiply -4 times \frac{1}{16}.
x=\frac{0±\sqrt{\frac{9}{4}}}{2\times \frac{1}{16}}
Multiply -\frac{1}{4} times -9.
x=\frac{0±\frac{3}{2}}{2\times \frac{1}{16}}
Take the square root of \frac{9}{4}.
x=\frac{0±\frac{3}{2}}{\frac{1}{8}}
Multiply 2 times \frac{1}{16}.
x=12
Now solve the equation x=\frac{0±\frac{3}{2}}{\frac{1}{8}} when ± is plus.
x=-12
Now solve the equation x=\frac{0±\frac{3}{2}}{\frac{1}{8}} when ± is minus.
x=12 x=-12
The equation is now solved.