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\frac{200}{0.5}=x^{2}
Divide both sides by 0.5.
\frac{2000}{5}=x^{2}
Expand \frac{200}{0.5} by multiplying both numerator and the denominator by 10.
400=x^{2}
Divide 2000 by 5 to get 400.
x^{2}=400
Swap sides so that all variable terms are on the left hand side.
x^{2}-400=0
Subtract 400 from both sides.
\left(x-20\right)\left(x+20\right)=0
Consider x^{2}-400. Rewrite x^{2}-400 as x^{2}-20^{2}. The difference of squares can be factored using the rule: a^{2}-b^{2}=\left(a-b\right)\left(a+b\right).
x=20 x=-20
To find equation solutions, solve x-20=0 and x+20=0.
\frac{200}{0.5}=x^{2}
Divide both sides by 0.5.
\frac{2000}{5}=x^{2}
Expand \frac{200}{0.5} by multiplying both numerator and the denominator by 10.
400=x^{2}
Divide 2000 by 5 to get 400.
x^{2}=400
Swap sides so that all variable terms are on the left hand side.
x=20 x=-20
Take the square root of both sides of the equation.
\frac{200}{0.5}=x^{2}
Divide both sides by 0.5.
\frac{2000}{5}=x^{2}
Expand \frac{200}{0.5} by multiplying both numerator and the denominator by 10.
400=x^{2}
Divide 2000 by 5 to get 400.
x^{2}=400
Swap sides so that all variable terms are on the left hand side.
x^{2}-400=0
Subtract 400 from both sides.
x=\frac{0±\sqrt{0^{2}-4\left(-400\right)}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, 0 for b, and -400 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\left(-400\right)}}{2}
Square 0.
x=\frac{0±\sqrt{1600}}{2}
Multiply -4 times -400.
x=\frac{0±40}{2}
Take the square root of 1600.
x=20
Now solve the equation x=\frac{0±40}{2} when ± is plus. Divide 40 by 2.
x=-20
Now solve the equation x=\frac{0±40}{2} when ± is minus. Divide -40 by 2.
x=20 x=-20
The equation is now solved.