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\left(x+1\right)\left(x+1\right)-xx=x^{2}-1
Variable x cannot be equal to any of the values -1,0,1 since division by zero is not defined. Multiply both sides of the equation by x\left(x-1\right)\left(x+1\right), the least common multiple of x^{2}-x,1-x^{2},x.
\left(x+1\right)^{2}-xx=x^{2}-1
Multiply x+1 and x+1 to get \left(x+1\right)^{2}.
x^{2}+2x+1-xx=x^{2}-1
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(x+1\right)^{2}.
x^{2}+2x+1-x^{2}=x^{2}-1
Multiply x and x to get x^{2}.
2x+1=x^{2}-1
Combine x^{2} and -x^{2} to get 0.
2x+1-x^{2}=-1
Subtract x^{2} from both sides.
2x+1-x^{2}+1=0
Add 1 to both sides.
2x+2-x^{2}=0
Add 1 and 1 to get 2.
-x^{2}+2x+2=0
All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. The quadratic formula gives two solutions, one when ± is addition and one when it is subtraction.
x=\frac{-2±\sqrt{2^{2}-4\left(-1\right)\times 2}}{2\left(-1\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -1 for a, 2 for b, and 2 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-2±\sqrt{4-4\left(-1\right)\times 2}}{2\left(-1\right)}
Square 2.
x=\frac{-2±\sqrt{4+4\times 2}}{2\left(-1\right)}
Multiply -4 times -1.
x=\frac{-2±\sqrt{4+8}}{2\left(-1\right)}
Multiply 4 times 2.
x=\frac{-2±\sqrt{12}}{2\left(-1\right)}
Add 4 to 8.
x=\frac{-2±2\sqrt{3}}{2\left(-1\right)}
Take the square root of 12.
x=\frac{-2±2\sqrt{3}}{-2}
Multiply 2 times -1.
x=\frac{2\sqrt{3}-2}{-2}
Now solve the equation x=\frac{-2±2\sqrt{3}}{-2} when ± is plus. Add -2 to 2\sqrt{3}.
x=1-\sqrt{3}
Divide -2+2\sqrt{3} by -2.
x=\frac{-2\sqrt{3}-2}{-2}
Now solve the equation x=\frac{-2±2\sqrt{3}}{-2} when ± is minus. Subtract 2\sqrt{3} from -2.
x=\sqrt{3}+1
Divide -2-2\sqrt{3} by -2.
x=1-\sqrt{3} x=\sqrt{3}+1
The equation is now solved.
\left(x+1\right)\left(x+1\right)-xx=x^{2}-1
Variable x cannot be equal to any of the values -1,0,1 since division by zero is not defined. Multiply both sides of the equation by x\left(x-1\right)\left(x+1\right), the least common multiple of x^{2}-x,1-x^{2},x.
\left(x+1\right)^{2}-xx=x^{2}-1
Multiply x+1 and x+1 to get \left(x+1\right)^{2}.
x^{2}+2x+1-xx=x^{2}-1
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(x+1\right)^{2}.
x^{2}+2x+1-x^{2}=x^{2}-1
Multiply x and x to get x^{2}.
2x+1=x^{2}-1
Combine x^{2} and -x^{2} to get 0.
2x+1-x^{2}=-1
Subtract x^{2} from both sides.
2x-x^{2}=-1-1
Subtract 1 from both sides.
2x-x^{2}=-2
Subtract 1 from -1 to get -2.
-x^{2}+2x=-2
Quadratic equations such as this one can be solved by completing the square. In order to complete the square, the equation must first be in the form x^{2}+bx=c.
\frac{-x^{2}+2x}{-1}=-\frac{2}{-1}
Divide both sides by -1.
x^{2}+\frac{2}{-1}x=-\frac{2}{-1}
Dividing by -1 undoes the multiplication by -1.
x^{2}-2x=-\frac{2}{-1}
Divide 2 by -1.
x^{2}-2x=2
Divide -2 by -1.
x^{2}-2x+1=2+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=3
Add 2 to 1.
\left(x-1\right)^{2}=3
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{3}
Take the square root of both sides of the equation.
x-1=\sqrt{3} x-1=-\sqrt{3}
Simplify.
x=\sqrt{3}+1 x=1-\sqrt{3}
Add 1 to both sides of the equation.