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100-xx=0
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by 100x, the least common multiple of x,100.
100-x^{2}=0
Multiply x and x to get x^{2}.
-x^{2}=-100
Subtract 100 from both sides. Anything subtracted from zero gives its negation.
x^{2}=\frac{-100}{-1}
Divide both sides by -1.
x^{2}=100
Fraction \frac{-100}{-1} can be simplified to 100 by removing the negative sign from both the numerator and the denominator.
x=10 x=-10
Take the square root of both sides of the equation.
100-xx=0
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by 100x, the least common multiple of x,100.
100-x^{2}=0
Multiply x and x to get x^{2}.
-x^{2}+100=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(-1\right)\times 100}}{2\left(-1\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -1 for a, 0 for b, and 100 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\left(-1\right)\times 100}}{2\left(-1\right)}
Square 0.
x=\frac{0±\sqrt{4\times 100}}{2\left(-1\right)}
Multiply -4 times -1.
x=\frac{0±\sqrt{400}}{2\left(-1\right)}
Multiply 4 times 100.
x=\frac{0±20}{2\left(-1\right)}
Take the square root of 400.
x=\frac{0±20}{-2}
Multiply 2 times -1.
x=-10
Now solve the equation x=\frac{0±20}{-2} when ± is plus. Divide 20 by -2.
x=10
Now solve the equation x=\frac{0±20}{-2} when ± is minus. Divide -20 by -2.
x=-10 x=10
The equation is now solved.