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Solve for x (complex solution)
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10=10x\left(x+2\right)
Variable x cannot be equal to any of the values -2,0 since division by zero is not defined. Multiply both sides of the equation by x\left(x+2\right).
10=10x^{2}+20x
Use the distributive property to multiply 10x by x+2.
10x^{2}+20x=10
Swap sides so that all variable terms are on the left hand side.
10x^{2}+20x-10=0
Subtract 10 from both sides.
x=\frac{-20±\sqrt{20^{2}-4\times 10\left(-10\right)}}{2\times 10}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 10 for a, 20 for b, and -10 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-20±\sqrt{400-4\times 10\left(-10\right)}}{2\times 10}
Square 20.
x=\frac{-20±\sqrt{400-40\left(-10\right)}}{2\times 10}
Multiply -4 times 10.
x=\frac{-20±\sqrt{400+400}}{2\times 10}
Multiply -40 times -10.
x=\frac{-20±\sqrt{800}}{2\times 10}
Add 400 to 400.
x=\frac{-20±20\sqrt{2}}{2\times 10}
Take the square root of 800.
x=\frac{-20±20\sqrt{2}}{20}
Multiply 2 times 10.
x=\frac{20\sqrt{2}-20}{20}
Now solve the equation x=\frac{-20±20\sqrt{2}}{20} when ± is plus. Add -20 to 20\sqrt{2}.
x=\sqrt{2}-1
Divide -20+20\sqrt{2} by 20.
x=\frac{-20\sqrt{2}-20}{20}
Now solve the equation x=\frac{-20±20\sqrt{2}}{20} when ± is minus. Subtract 20\sqrt{2} from -20.
x=-\sqrt{2}-1
Divide -20-20\sqrt{2} by 20.
x=\sqrt{2}-1 x=-\sqrt{2}-1
The equation is now solved.
10=10x\left(x+2\right)
Variable x cannot be equal to any of the values -2,0 since division by zero is not defined. Multiply both sides of the equation by x\left(x+2\right).
10=10x^{2}+20x
Use the distributive property to multiply 10x by x+2.
10x^{2}+20x=10
Swap sides so that all variable terms are on the left hand side.
\frac{10x^{2}+20x}{10}=\frac{10}{10}
Divide both sides by 10.
x^{2}+\frac{20}{10}x=\frac{10}{10}
Dividing by 10 undoes the multiplication by 10.
x^{2}+2x=\frac{10}{10}
Divide 20 by 10.
x^{2}+2x=1
Divide 10 by 10.
x^{2}+2x+1^{2}=1+1^{2}
Divide 2, the coefficient of the x term, by 2 to get 1. Then add the square of 1 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}+2x+1=1+1
Square 1.
x^{2}+2x+1=2
Add 1 to 1.
\left(x+1\right)^{2}=2
Factor x^{2}+2x+1. 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+1\right)^{2}}=\sqrt{2}
Take the square root of both sides of the equation.
x+1=\sqrt{2} x+1=-\sqrt{2}
Simplify.
x=\sqrt{2}-1 x=-\sqrt{2}-1
Subtract 1 from both sides of the equation.
10=10x\left(x+2\right)
Variable x cannot be equal to any of the values -2,0 since division by zero is not defined. Multiply both sides of the equation by x\left(x+2\right).
10=10x^{2}+20x
Use the distributive property to multiply 10x by x+2.
10x^{2}+20x=10
Swap sides so that all variable terms are on the left hand side.
10x^{2}+20x-10=0
Subtract 10 from both sides.
x=\frac{-20±\sqrt{20^{2}-4\times 10\left(-10\right)}}{2\times 10}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 10 for a, 20 for b, and -10 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-20±\sqrt{400-4\times 10\left(-10\right)}}{2\times 10}
Square 20.
x=\frac{-20±\sqrt{400-40\left(-10\right)}}{2\times 10}
Multiply -4 times 10.
x=\frac{-20±\sqrt{400+400}}{2\times 10}
Multiply -40 times -10.
x=\frac{-20±\sqrt{800}}{2\times 10}
Add 400 to 400.
x=\frac{-20±20\sqrt{2}}{2\times 10}
Take the square root of 800.
x=\frac{-20±20\sqrt{2}}{20}
Multiply 2 times 10.
x=\frac{20\sqrt{2}-20}{20}
Now solve the equation x=\frac{-20±20\sqrt{2}}{20} when ± is plus. Add -20 to 20\sqrt{2}.
x=\sqrt{2}-1
Divide -20+20\sqrt{2} by 20.
x=\frac{-20\sqrt{2}-20}{20}
Now solve the equation x=\frac{-20±20\sqrt{2}}{20} when ± is minus. Subtract 20\sqrt{2} from -20.
x=-\sqrt{2}-1
Divide -20-20\sqrt{2} by 20.
x=\sqrt{2}-1 x=-\sqrt{2}-1
The equation is now solved.
10=10x\left(x+2\right)
Variable x cannot be equal to any of the values -2,0 since division by zero is not defined. Multiply both sides of the equation by x\left(x+2\right).
10=10x^{2}+20x
Use the distributive property to multiply 10x by x+2.
10x^{2}+20x=10
Swap sides so that all variable terms are on the left hand side.
\frac{10x^{2}+20x}{10}=\frac{10}{10}
Divide both sides by 10.
x^{2}+\frac{20}{10}x=\frac{10}{10}
Dividing by 10 undoes the multiplication by 10.
x^{2}+2x=\frac{10}{10}
Divide 20 by 10.
x^{2}+2x=1
Divide 10 by 10.
x^{2}+2x+1^{2}=1+1^{2}
Divide 2, the coefficient of the x term, by 2 to get 1. Then add the square of 1 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}+2x+1=1+1
Square 1.
x^{2}+2x+1=2
Add 1 to 1.
\left(x+1\right)^{2}=2
Factor x^{2}+2x+1. 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+1\right)^{2}}=\sqrt{2}
Take the square root of both sides of the equation.
x+1=\sqrt{2} x+1=-\sqrt{2}
Simplify.
x=\sqrt{2}-1 x=-\sqrt{2}-1
Subtract 1 from both sides of the equation.