Solve for x
x=200
x=-200
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x^{2}=100\times 20^{2}
Calculate 10 to the power of 2 and get 100.
x^{2}=100\times 400
Calculate 20 to the power of 2 and get 400.
x^{2}=40000
Multiply 100 and 400 to get 40000.
x^{2}-40000=0
Subtract 40000 from both sides.
\left(x-200\right)\left(x+200\right)=0
Consider x^{2}-40000. Rewrite x^{2}-40000 as x^{2}-200^{2}. The difference of squares can be factored using the rule: a^{2}-b^{2}=\left(a-b\right)\left(a+b\right).
x=200 x=-200
To find equation solutions, solve x-200=0 and x+200=0.
x^{2}=100\times 20^{2}
Calculate 10 to the power of 2 and get 100.
x^{2}=100\times 400
Calculate 20 to the power of 2 and get 400.
x^{2}=40000
Multiply 100 and 400 to get 40000.
x=200 x=-200
Take the square root of both sides of the equation.
x^{2}=100\times 20^{2}
Calculate 10 to the power of 2 and get 100.
x^{2}=100\times 400
Calculate 20 to the power of 2 and get 400.
x^{2}=40000
Multiply 100 and 400 to get 40000.
x^{2}-40000=0
Subtract 40000 from both sides.
x=\frac{0±\sqrt{0^{2}-4\left(-40000\right)}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, 0 for b, and -40000 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\left(-40000\right)}}{2}
Square 0.
x=\frac{0±\sqrt{160000}}{2}
Multiply -4 times -40000.
x=\frac{0±400}{2}
Take the square root of 160000.
x=200
Now solve the equation x=\frac{0±400}{2} when ± is plus. Divide 400 by 2.
x=-200
Now solve the equation x=\frac{0±400}{2} when ± is minus. Divide -400 by 2.
x=200 x=-200
The equation is now solved.
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