Solve for x
x=2\sqrt{2}+3\approx 5.828427125
x=3-2\sqrt{2}\approx 0.171572875
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2x\left(6-x\right)=2
Multiply both sides by 2.
12x-2x^{2}=2
Use the distributive property to multiply 2x by 6-x.
12x-2x^{2}-2=0
Subtract 2 from both sides.
-2x^{2}+12x-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{-12±\sqrt{12^{2}-4\left(-2\right)\left(-2\right)}}{2\left(-2\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -2 for a, 12 for b, and -2 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-12±\sqrt{144-4\left(-2\right)\left(-2\right)}}{2\left(-2\right)}
Square 12.
x=\frac{-12±\sqrt{144+8\left(-2\right)}}{2\left(-2\right)}
Multiply -4 times -2.
x=\frac{-12±\sqrt{144-16}}{2\left(-2\right)}
Multiply 8 times -2.
x=\frac{-12±\sqrt{128}}{2\left(-2\right)}
Add 144 to -16.
x=\frac{-12±8\sqrt{2}}{2\left(-2\right)}
Take the square root of 128.
x=\frac{-12±8\sqrt{2}}{-4}
Multiply 2 times -2.
x=\frac{8\sqrt{2}-12}{-4}
Now solve the equation x=\frac{-12±8\sqrt{2}}{-4} when ± is plus. Add -12 to 8\sqrt{2}.
x=3-2\sqrt{2}
Divide -12+8\sqrt{2} by -4.
x=\frac{-8\sqrt{2}-12}{-4}
Now solve the equation x=\frac{-12±8\sqrt{2}}{-4} when ± is minus. Subtract 8\sqrt{2} from -12.
x=2\sqrt{2}+3
Divide -12-8\sqrt{2} by -4.
x=3-2\sqrt{2} x=2\sqrt{2}+3
The equation is now solved.
2x\left(6-x\right)=2
Multiply both sides by 2.
12x-2x^{2}=2
Use the distributive property to multiply 2x by 6-x.
-2x^{2}+12x=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{-2x^{2}+12x}{-2}=\frac{2}{-2}
Divide both sides by -2.
x^{2}+\frac{12}{-2}x=\frac{2}{-2}
Dividing by -2 undoes the multiplication by -2.
x^{2}-6x=\frac{2}{-2}
Divide 12 by -2.
x^{2}-6x=-1
Divide 2 by -2.
x^{2}-6x+\left(-3\right)^{2}=-1+\left(-3\right)^{2}
Divide -6, the coefficient of the x term, by 2 to get -3. Then add the square of -3 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-6x+9=-1+9
Square -3.
x^{2}-6x+9=8
Add -1 to 9.
\left(x-3\right)^{2}=8
Factor x^{2}-6x+9. 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-3\right)^{2}}=\sqrt{8}
Take the square root of both sides of the equation.
x-3=2\sqrt{2} x-3=-2\sqrt{2}
Simplify.
x=2\sqrt{2}+3 x=3-2\sqrt{2}
Add 3 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}