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360\times 5=x\left(x+5\right)
Variable x cannot be equal to any of the values -5,0 since division by zero is not defined. Multiply both sides of the equation by x\left(x+5\right).
1800=x\left(x+5\right)
Multiply 360 and 5 to get 1800.
1800=x^{2}+5x
Use the distributive property to multiply x by x+5.
x^{2}+5x=1800
Swap sides so that all variable terms are on the left hand side.
x^{2}+5x-1800=0
Subtract 1800 from both sides.
x=\frac{-5±\sqrt{5^{2}-4\left(-1800\right)}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, 5 for b, and -1800 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-5±\sqrt{25-4\left(-1800\right)}}{2}
Square 5.
x=\frac{-5±\sqrt{25+7200}}{2}
Multiply -4 times -1800.
x=\frac{-5±\sqrt{7225}}{2}
Add 25 to 7200.
x=\frac{-5±85}{2}
Take the square root of 7225.
x=\frac{80}{2}
Now solve the equation x=\frac{-5±85}{2} when ± is plus. Add -5 to 85.
x=40
Divide 80 by 2.
x=-\frac{90}{2}
Now solve the equation x=\frac{-5±85}{2} when ± is minus. Subtract 85 from -5.
x=-45
Divide -90 by 2.
x=40 x=-45
The equation is now solved.
360\times 5=x\left(x+5\right)
Variable x cannot be equal to any of the values -5,0 since division by zero is not defined. Multiply both sides of the equation by x\left(x+5\right).
1800=x\left(x+5\right)
Multiply 360 and 5 to get 1800.
1800=x^{2}+5x
Use the distributive property to multiply x by x+5.
x^{2}+5x=1800
Swap sides so that all variable terms are on the left hand side.
x^{2}+5x+\left(\frac{5}{2}\right)^{2}=1800+\left(\frac{5}{2}\right)^{2}
Divide 5, the coefficient of the x term, by 2 to get \frac{5}{2}. Then add the square of \frac{5}{2} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}+5x+\frac{25}{4}=1800+\frac{25}{4}
Square \frac{5}{2} by squaring both the numerator and the denominator of the fraction.
x^{2}+5x+\frac{25}{4}=\frac{7225}{4}
Add 1800 to \frac{25}{4}.
\left(x+\frac{5}{2}\right)^{2}=\frac{7225}{4}
Factor x^{2}+5x+\frac{25}{4}. In general, when x^{2}+bx+c is a perfect square, it can always be factored as \left(x+\frac{b}{2}\right)^{2}.
\sqrt{\left(x+\frac{5}{2}\right)^{2}}=\sqrt{\frac{7225}{4}}
Take the square root of both sides of the equation.
x+\frac{5}{2}=\frac{85}{2} x+\frac{5}{2}=-\frac{85}{2}
Simplify.
x=40 x=-45
Subtract \frac{5}{2} from both sides of the equation.