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2x=6-7x+x^{2}
Use the distributive property to multiply 6-x by 1-x and combine like terms.
2x-6=-7x+x^{2}
Subtract 6 from both sides.
2x-6+7x=x^{2}
Add 7x to both sides.
9x-6=x^{2}
Combine 2x and 7x to get 9x.
9x-6-x^{2}=0
Subtract x^{2} from both sides.
-x^{2}+9x-6=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{-9±\sqrt{9^{2}-4\left(-1\right)\left(-6\right)}}{2\left(-1\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -1 for a, 9 for b, and -6 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-9±\sqrt{81-4\left(-1\right)\left(-6\right)}}{2\left(-1\right)}
Square 9.
x=\frac{-9±\sqrt{81+4\left(-6\right)}}{2\left(-1\right)}
Multiply -4 times -1.
x=\frac{-9±\sqrt{81-24}}{2\left(-1\right)}
Multiply 4 times -6.
x=\frac{-9±\sqrt{57}}{2\left(-1\right)}
Add 81 to -24.
x=\frac{-9±\sqrt{57}}{-2}
Multiply 2 times -1.
x=\frac{\sqrt{57}-9}{-2}
Now solve the equation x=\frac{-9±\sqrt{57}}{-2} when ± is plus. Add -9 to \sqrt{57}.
x=\frac{9-\sqrt{57}}{2}
Divide -9+\sqrt{57} by -2.
x=\frac{-\sqrt{57}-9}{-2}
Now solve the equation x=\frac{-9±\sqrt{57}}{-2} when ± is minus. Subtract \sqrt{57} from -9.
x=\frac{\sqrt{57}+9}{2}
Divide -9-\sqrt{57} by -2.
x=\frac{9-\sqrt{57}}{2} x=\frac{\sqrt{57}+9}{2}
The equation is now solved.
2x=6-7x+x^{2}
Use the distributive property to multiply 6-x by 1-x and combine like terms.
2x+7x=6+x^{2}
Add 7x to both sides.
9x=6+x^{2}
Combine 2x and 7x to get 9x.
9x-x^{2}=6
Subtract x^{2} from both sides.
-x^{2}+9x=6
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}+9x}{-1}=\frac{6}{-1}
Divide both sides by -1.
x^{2}+\frac{9}{-1}x=\frac{6}{-1}
Dividing by -1 undoes the multiplication by -1.
x^{2}-9x=\frac{6}{-1}
Divide 9 by -1.
x^{2}-9x=-6
Divide 6 by -1.
x^{2}-9x+\left(-\frac{9}{2}\right)^{2}=-6+\left(-\frac{9}{2}\right)^{2}
Divide -9, the coefficient of the x term, by 2 to get -\frac{9}{2}. Then add the square of -\frac{9}{2} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-9x+\frac{81}{4}=-6+\frac{81}{4}
Square -\frac{9}{2} by squaring both the numerator and the denominator of the fraction.
x^{2}-9x+\frac{81}{4}=\frac{57}{4}
Add -6 to \frac{81}{4}.
\left(x-\frac{9}{2}\right)^{2}=\frac{57}{4}
Factor x^{2}-9x+\frac{81}{4}. 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-\frac{9}{2}\right)^{2}}=\sqrt{\frac{57}{4}}
Take the square root of both sides of the equation.
x-\frac{9}{2}=\frac{\sqrt{57}}{2} x-\frac{9}{2}=-\frac{\sqrt{57}}{2}
Simplify.
x=\frac{\sqrt{57}+9}{2} x=\frac{9-\sqrt{57}}{2}
Add \frac{9}{2} to both sides of the equation.