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x^{2}-20=0
Add -24 and 4 to get -20.
x^{2}=20
Add 20 to both sides. Anything plus zero gives itself.
x=2\sqrt{5} x=-2\sqrt{5}
Take the square root of both sides of the equation.
x^{2}-20=0
Add -24 and 4 to get -20.
x=\frac{0±\sqrt{0^{2}-4\left(-20\right)}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, 0 for b, and -20 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\left(-20\right)}}{2}
Square 0.
x=\frac{0±\sqrt{80}}{2}
Multiply -4 times -20.
x=\frac{0±4\sqrt{5}}{2}
Take the square root of 80.
x=2\sqrt{5}
Now solve the equation x=\frac{0±4\sqrt{5}}{2} when ± is plus.
x=-2\sqrt{5}
Now solve the equation x=\frac{0±4\sqrt{5}}{2} when ± is minus.
x=2\sqrt{5} x=-2\sqrt{5}
The equation is now solved.