Solve for x
x = \frac{\sqrt{5} + 7}{2} \approx 4.618033989
x = \frac{7 - \sqrt{5}}{2} \approx 2.381966011
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x^{2}-6x+9=x-2
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(x-3\right)^{2}.
x^{2}-6x+9-x=-2
Subtract x from both sides.
x^{2}-7x+9=-2
Combine -6x and -x to get -7x.
x^{2}-7x+9+2=0
Add 2 to both sides.
x^{2}-7x+11=0
Add 9 and 2 to get 11.
x=\frac{-\left(-7\right)±\sqrt{\left(-7\right)^{2}-4\times 11}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, -7 for b, and 11 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-\left(-7\right)±\sqrt{49-4\times 11}}{2}
Square -7.
x=\frac{-\left(-7\right)±\sqrt{49-44}}{2}
Multiply -4 times 11.
x=\frac{-\left(-7\right)±\sqrt{5}}{2}
Add 49 to -44.
x=\frac{7±\sqrt{5}}{2}
The opposite of -7 is 7.
x=\frac{\sqrt{5}+7}{2}
Now solve the equation x=\frac{7±\sqrt{5}}{2} when ± is plus. Add 7 to \sqrt{5}.
x=\frac{7-\sqrt{5}}{2}
Now solve the equation x=\frac{7±\sqrt{5}}{2} when ± is minus. Subtract \sqrt{5} from 7.
x=\frac{\sqrt{5}+7}{2} x=\frac{7-\sqrt{5}}{2}
The equation is now solved.
x^{2}-6x+9=x-2
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(x-3\right)^{2}.
x^{2}-6x+9-x=-2
Subtract x from both sides.
x^{2}-7x+9=-2
Combine -6x and -x to get -7x.
x^{2}-7x=-2-9
Subtract 9 from both sides.
x^{2}-7x=-11
Subtract 9 from -2 to get -11.
x^{2}-7x+\left(-\frac{7}{2}\right)^{2}=-11+\left(-\frac{7}{2}\right)^{2}
Divide -7, the coefficient of the x term, by 2 to get -\frac{7}{2}. Then add the square of -\frac{7}{2} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-7x+\frac{49}{4}=-11+\frac{49}{4}
Square -\frac{7}{2} by squaring both the numerator and the denominator of the fraction.
x^{2}-7x+\frac{49}{4}=\frac{5}{4}
Add -11 to \frac{49}{4}.
\left(x-\frac{7}{2}\right)^{2}=\frac{5}{4}
Factor x^{2}-7x+\frac{49}{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{7}{2}\right)^{2}}=\sqrt{\frac{5}{4}}
Take the square root of both sides of the equation.
x-\frac{7}{2}=\frac{\sqrt{5}}{2} x-\frac{7}{2}=-\frac{\sqrt{5}}{2}
Simplify.
x=\frac{\sqrt{5}+7}{2} x=\frac{7-\sqrt{5}}{2}
Add \frac{7}{2} to both sides of the equation.
Examples
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{ 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}