Solve for x
x=2\sqrt{5}+6\approx 10.472135955
x=6-2\sqrt{5}\approx 1.527864045
Graph
Share
Copied to clipboard
x\left(x-2\right)-8\left(x-2\right)=2x
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by 8x, the least common multiple of 8,x,4.
x^{2}-2x-8\left(x-2\right)=2x
Use the distributive property to multiply x by x-2.
x^{2}-2x-8x+16=2x
Use the distributive property to multiply -8 by x-2.
x^{2}-10x+16=2x
Combine -2x and -8x to get -10x.
x^{2}-10x+16-2x=0
Subtract 2x from both sides.
x^{2}-12x+16=0
Combine -10x and -2x to get -12x.
x=\frac{-\left(-12\right)±\sqrt{\left(-12\right)^{2}-4\times 16}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, -12 for b, and 16 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-\left(-12\right)±\sqrt{144-4\times 16}}{2}
Square -12.
x=\frac{-\left(-12\right)±\sqrt{144-64}}{2}
Multiply -4 times 16.
x=\frac{-\left(-12\right)±\sqrt{80}}{2}
Add 144 to -64.
x=\frac{-\left(-12\right)±4\sqrt{5}}{2}
Take the square root of 80.
x=\frac{12±4\sqrt{5}}{2}
The opposite of -12 is 12.
x=\frac{4\sqrt{5}+12}{2}
Now solve the equation x=\frac{12±4\sqrt{5}}{2} when ± is plus. Add 12 to 4\sqrt{5}.
x=2\sqrt{5}+6
Divide 12+4\sqrt{5} by 2.
x=\frac{12-4\sqrt{5}}{2}
Now solve the equation x=\frac{12±4\sqrt{5}}{2} when ± is minus. Subtract 4\sqrt{5} from 12.
x=6-2\sqrt{5}
Divide 12-4\sqrt{5} by 2.
x=2\sqrt{5}+6 x=6-2\sqrt{5}
The equation is now solved.
x\left(x-2\right)-8\left(x-2\right)=2x
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by 8x, the least common multiple of 8,x,4.
x^{2}-2x-8\left(x-2\right)=2x
Use the distributive property to multiply x by x-2.
x^{2}-2x-8x+16=2x
Use the distributive property to multiply -8 by x-2.
x^{2}-10x+16=2x
Combine -2x and -8x to get -10x.
x^{2}-10x+16-2x=0
Subtract 2x from both sides.
x^{2}-12x+16=0
Combine -10x and -2x to get -12x.
x^{2}-12x=-16
Subtract 16 from both sides. Anything subtracted from zero gives its negation.
x^{2}-12x+\left(-6\right)^{2}=-16+\left(-6\right)^{2}
Divide -12, the coefficient of the x term, by 2 to get -6. Then add the square of -6 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-12x+36=-16+36
Square -6.
x^{2}-12x+36=20
Add -16 to 36.
\left(x-6\right)^{2}=20
Factor x^{2}-12x+36. 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-6\right)^{2}}=\sqrt{20}
Take the square root of both sides of the equation.
x-6=2\sqrt{5} x-6=-2\sqrt{5}
Simplify.
x=2\sqrt{5}+6 x=6-2\sqrt{5}
Add 6 to both sides of the equation.
Examples
Quadratic equation
{ x } ^ { 2 } - 4 x - 5 = 0
Trigonometry
4 \sin \theta \cos \theta = 2 \sin \theta
Linear equation
y = 3x + 4
Arithmetic
699 * 533
Matrix
\left[ \begin{array} { l l } { 2 } & { 3 } \\ { 5 } & { 4 } \end{array} \right] \left[ \begin{array} { l l l } { 2 } & { 0 } & { 3 } \\ { -1 } & { 1 } & { 5 } \end{array} \right]
Simultaneous equation
\left. \begin{cases} { 8x+2y = 46 } \\ { 7x+3y = 47 } \end{cases} \right.
Differentiation
\frac { d } { d x } \frac { ( 3 x ^ { 2 } - 2 ) } { ( x - 5 ) }
Integration
\int _ { 0 } ^ { 1 } x e ^ { - x ^ { 2 } } d x
Limits
\lim _{x \rightarrow-3} \frac{x^{2}-9}{x^{2}+2 x-3}