Skip to main content
Solve for x
Tick mark Image
Graph

Similar Problems from Web Search

Share

x^{2}-x=x+1
Variable x cannot be equal to -1 since division by zero is not defined. Multiply both sides of the equation by x+1.
x^{2}-x-x=1
Subtract x from both sides.
x^{2}-2x=1
Combine -x and -x to get -2x.
x^{2}-2x-1=0
Subtract 1 from both sides.
x=\frac{-\left(-2\right)±\sqrt{\left(-2\right)^{2}-4\left(-1\right)}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, -2 for b, and -1 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-\left(-2\right)±\sqrt{4-4\left(-1\right)}}{2}
Square -2.
x=\frac{-\left(-2\right)±\sqrt{4+4}}{2}
Multiply -4 times -1.
x=\frac{-\left(-2\right)±\sqrt{8}}{2}
Add 4 to 4.
x=\frac{-\left(-2\right)±2\sqrt{2}}{2}
Take the square root of 8.
x=\frac{2±2\sqrt{2}}{2}
The opposite of -2 is 2.
x=\frac{2\sqrt{2}+2}{2}
Now solve the equation x=\frac{2±2\sqrt{2}}{2} when ± is plus. Add 2 to 2\sqrt{2}.
x=\sqrt{2}+1
Divide 2+2\sqrt{2} by 2.
x=\frac{2-2\sqrt{2}}{2}
Now solve the equation x=\frac{2±2\sqrt{2}}{2} when ± is minus. Subtract 2\sqrt{2} from 2.
x=1-\sqrt{2}
Divide 2-2\sqrt{2} by 2.
x=\sqrt{2}+1 x=1-\sqrt{2}
The equation is now solved.
x^{2}-x=x+1
Variable x cannot be equal to -1 since division by zero is not defined. Multiply both sides of the equation by x+1.
x^{2}-x-x=1
Subtract x from both sides.
x^{2}-2x=1
Combine -x and -x to get -2x.
x^{2}-2x+1=1+1
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=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=1-\sqrt{2}
Add 1 to both sides of the equation.