Solve for x
x=-4
x=0
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x^{2}-x-6=\left(3x-2\right)\left(x+3\right)
Use the distributive property to multiply x+2 by x-3 and combine like terms.
x^{2}-x-6=3x^{2}+7x-6
Use the distributive property to multiply 3x-2 by x+3 and combine like terms.
x^{2}-x-6-3x^{2}=7x-6
Subtract 3x^{2} from both sides.
-2x^{2}-x-6=7x-6
Combine x^{2} and -3x^{2} to get -2x^{2}.
-2x^{2}-x-6-7x=-6
Subtract 7x from both sides.
-2x^{2}-8x-6=-6
Combine -x and -7x to get -8x.
-2x^{2}-8x-6+6=0
Add 6 to both sides.
-2x^{2}-8x=0
Add -6 and 6 to get 0.
x=\frac{-\left(-8\right)±\sqrt{\left(-8\right)^{2}}}{2\left(-2\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -2 for a, -8 for b, and 0 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-\left(-8\right)±8}{2\left(-2\right)}
Take the square root of \left(-8\right)^{2}.
x=\frac{8±8}{2\left(-2\right)}
The opposite of -8 is 8.
x=\frac{8±8}{-4}
Multiply 2 times -2.
x=\frac{16}{-4}
Now solve the equation x=\frac{8±8}{-4} when ± is plus. Add 8 to 8.
x=-4
Divide 16 by -4.
x=\frac{0}{-4}
Now solve the equation x=\frac{8±8}{-4} when ± is minus. Subtract 8 from 8.
x=0
Divide 0 by -4.
x=-4 x=0
The equation is now solved.
x^{2}-x-6=\left(3x-2\right)\left(x+3\right)
Use the distributive property to multiply x+2 by x-3 and combine like terms.
x^{2}-x-6=3x^{2}+7x-6
Use the distributive property to multiply 3x-2 by x+3 and combine like terms.
x^{2}-x-6-3x^{2}=7x-6
Subtract 3x^{2} from both sides.
-2x^{2}-x-6=7x-6
Combine x^{2} and -3x^{2} to get -2x^{2}.
-2x^{2}-x-6-7x=-6
Subtract 7x from both sides.
-2x^{2}-8x-6=-6
Combine -x and -7x to get -8x.
-2x^{2}-8x=-6+6
Add 6 to both sides.
-2x^{2}-8x=0
Add -6 and 6 to get 0.
\frac{-2x^{2}-8x}{-2}=\frac{0}{-2}
Divide both sides by -2.
x^{2}+\left(-\frac{8}{-2}\right)x=\frac{0}{-2}
Dividing by -2 undoes the multiplication by -2.
x^{2}+4x=\frac{0}{-2}
Divide -8 by -2.
x^{2}+4x=0
Divide 0 by -2.
x^{2}+4x+2^{2}=2^{2}
Divide 4, the coefficient of the x term, by 2 to get 2. Then add the square of 2 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}+4x+4=4
Square 2.
\left(x+2\right)^{2}=4
Factor x^{2}+4x+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+2\right)^{2}}=\sqrt{4}
Take the square root of both sides of the equation.
x+2=2 x+2=-2
Simplify.
x=0 x=-4
Subtract 2 from both sides of the equation.
Examples
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{ x } ^ { 2 } - 4 x - 5 = 0
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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
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