Skip to main content
Solve for x
Tick mark Image
Graph

Similar Problems from Web Search

Share

x^{2}-10x=x\times 3\left(x-10\right)
Variable x cannot be equal to 10 since division by zero is not defined. Multiply both sides of the equation by 3\left(x-10\right).
x^{2}-10x=3x^{2}-10x\times 3
Use the distributive property to multiply x\times 3 by x-10.
x^{2}-10x=3x^{2}-30x
Multiply -10 and 3 to get -30.
x^{2}-10x-3x^{2}=-30x
Subtract 3x^{2} from both sides.
-2x^{2}-10x=-30x
Combine x^{2} and -3x^{2} to get -2x^{2}.
-2x^{2}-10x+30x=0
Add 30x to both sides.
-2x^{2}+20x=0
Combine -10x and 30x to get 20x.
x\left(-2x+20\right)=0
Factor out x.
x=0 x=10
To find equation solutions, solve x=0 and -2x+20=0.
x=0
Variable x cannot be equal to 10.
x^{2}-10x=x\times 3\left(x-10\right)
Variable x cannot be equal to 10 since division by zero is not defined. Multiply both sides of the equation by 3\left(x-10\right).
x^{2}-10x=3x^{2}-10x\times 3
Use the distributive property to multiply x\times 3 by x-10.
x^{2}-10x=3x^{2}-30x
Multiply -10 and 3 to get -30.
x^{2}-10x-3x^{2}=-30x
Subtract 3x^{2} from both sides.
-2x^{2}-10x=-30x
Combine x^{2} and -3x^{2} to get -2x^{2}.
-2x^{2}-10x+30x=0
Add 30x to both sides.
-2x^{2}+20x=0
Combine -10x and 30x to get 20x.
x=\frac{-20±\sqrt{20^{2}}}{2\left(-2\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -2 for a, 20 for b, and 0 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-20±20}{2\left(-2\right)}
Take the square root of 20^{2}.
x=\frac{-20±20}{-4}
Multiply 2 times -2.
x=\frac{0}{-4}
Now solve the equation x=\frac{-20±20}{-4} when ± is plus. Add -20 to 20.
x=0
Divide 0 by -4.
x=-\frac{40}{-4}
Now solve the equation x=\frac{-20±20}{-4} when ± is minus. Subtract 20 from -20.
x=10
Divide -40 by -4.
x=0 x=10
The equation is now solved.
x=0
Variable x cannot be equal to 10.
x^{2}-10x=x\times 3\left(x-10\right)
Variable x cannot be equal to 10 since division by zero is not defined. Multiply both sides of the equation by 3\left(x-10\right).
x^{2}-10x=3x^{2}-10x\times 3
Use the distributive property to multiply x\times 3 by x-10.
x^{2}-10x=3x^{2}-30x
Multiply -10 and 3 to get -30.
x^{2}-10x-3x^{2}=-30x
Subtract 3x^{2} from both sides.
-2x^{2}-10x=-30x
Combine x^{2} and -3x^{2} to get -2x^{2}.
-2x^{2}-10x+30x=0
Add 30x to both sides.
-2x^{2}+20x=0
Combine -10x and 30x to get 20x.
\frac{-2x^{2}+20x}{-2}=\frac{0}{-2}
Divide both sides by -2.
x^{2}+\frac{20}{-2}x=\frac{0}{-2}
Dividing by -2 undoes the multiplication by -2.
x^{2}-10x=\frac{0}{-2}
Divide 20 by -2.
x^{2}-10x=0
Divide 0 by -2.
x^{2}-10x+\left(-5\right)^{2}=\left(-5\right)^{2}
Divide -10, the coefficient of the x term, by 2 to get -5. Then add the square of -5 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-10x+25=25
Square -5.
\left(x-5\right)^{2}=25
Factor x^{2}-10x+25. 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-5\right)^{2}}=\sqrt{25}
Take the square root of both sides of the equation.
x-5=5 x-5=-5
Simplify.
x=10 x=0
Add 5 to both sides of the equation.
x=0
Variable x cannot be equal to 10.