Solve for x
x=-3
x=-1
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2\left(1-3\right)+12x-3\left(5x+2\right)-2\left(x-2\right)\left(x+2\right)=5x+4
Multiply both sides of the equation by 6, the least common multiple of 3,2,6.
2\left(-2\right)+12x-3\left(5x+2\right)-2\left(x-2\right)\left(x+2\right)=5x+4
Subtract 3 from 1 to get -2.
-4+12x-3\left(5x+2\right)-2\left(x-2\right)\left(x+2\right)=5x+4
Multiply 2 and -2 to get -4.
-4+12x-15x-6-2\left(x-2\right)\left(x+2\right)=5x+4
Use the distributive property to multiply -3 by 5x+2.
-4-3x-6-2\left(x-2\right)\left(x+2\right)=5x+4
Combine 12x and -15x to get -3x.
-10-3x-2\left(x-2\right)\left(x+2\right)=5x+4
Subtract 6 from -4 to get -10.
-10-3x+\left(-2x+4\right)\left(x+2\right)=5x+4
Use the distributive property to multiply -2 by x-2.
-10-3x-2x^{2}+8=5x+4
Use the distributive property to multiply -2x+4 by x+2 and combine like terms.
-2-3x-2x^{2}=5x+4
Add -10 and 8 to get -2.
-2-3x-2x^{2}-5x=4
Subtract 5x from both sides.
-2-8x-2x^{2}=4
Combine -3x and -5x to get -8x.
-2-8x-2x^{2}-4=0
Subtract 4 from both sides.
-6-8x-2x^{2}=0
Subtract 4 from -2 to get -6.
-2x^{2}-8x-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{-\left(-8\right)±\sqrt{\left(-8\right)^{2}-4\left(-2\right)\left(-6\right)}}{2\left(-2\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -2 for a, -8 for b, and -6 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-\left(-8\right)±\sqrt{64-4\left(-2\right)\left(-6\right)}}{2\left(-2\right)}
Square -8.
x=\frac{-\left(-8\right)±\sqrt{64+8\left(-6\right)}}{2\left(-2\right)}
Multiply -4 times -2.
x=\frac{-\left(-8\right)±\sqrt{64-48}}{2\left(-2\right)}
Multiply 8 times -6.
x=\frac{-\left(-8\right)±\sqrt{16}}{2\left(-2\right)}
Add 64 to -48.
x=\frac{-\left(-8\right)±4}{2\left(-2\right)}
Take the square root of 16.
x=\frac{8±4}{2\left(-2\right)}
The opposite of -8 is 8.
x=\frac{8±4}{-4}
Multiply 2 times -2.
x=\frac{12}{-4}
Now solve the equation x=\frac{8±4}{-4} when ± is plus. Add 8 to 4.
x=-3
Divide 12 by -4.
x=\frac{4}{-4}
Now solve the equation x=\frac{8±4}{-4} when ± is minus. Subtract 4 from 8.
x=-1
Divide 4 by -4.
x=-3 x=-1
The equation is now solved.
2\left(1-3\right)+12x-3\left(5x+2\right)-2\left(x-2\right)\left(x+2\right)=5x+4
Multiply both sides of the equation by 6, the least common multiple of 3,2,6.
2\left(-2\right)+12x-3\left(5x+2\right)-2\left(x-2\right)\left(x+2\right)=5x+4
Subtract 3 from 1 to get -2.
-4+12x-3\left(5x+2\right)-2\left(x-2\right)\left(x+2\right)=5x+4
Multiply 2 and -2 to get -4.
-4+12x-15x-6-2\left(x-2\right)\left(x+2\right)=5x+4
Use the distributive property to multiply -3 by 5x+2.
-4-3x-6-2\left(x-2\right)\left(x+2\right)=5x+4
Combine 12x and -15x to get -3x.
-10-3x-2\left(x-2\right)\left(x+2\right)=5x+4
Subtract 6 from -4 to get -10.
-10-3x+\left(-2x+4\right)\left(x+2\right)=5x+4
Use the distributive property to multiply -2 by x-2.
-10-3x-2x^{2}+8=5x+4
Use the distributive property to multiply -2x+4 by x+2 and combine like terms.
-2-3x-2x^{2}=5x+4
Add -10 and 8 to get -2.
-2-3x-2x^{2}-5x=4
Subtract 5x from both sides.
-2-8x-2x^{2}=4
Combine -3x and -5x to get -8x.
-8x-2x^{2}=4+2
Add 2 to both sides.
-8x-2x^{2}=6
Add 4 and 2 to get 6.
-2x^{2}-8x=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{-2x^{2}-8x}{-2}=\frac{6}{-2}
Divide both sides by -2.
x^{2}+\left(-\frac{8}{-2}\right)x=\frac{6}{-2}
Dividing by -2 undoes the multiplication by -2.
x^{2}+4x=\frac{6}{-2}
Divide -8 by -2.
x^{2}+4x=-3
Divide 6 by -2.
x^{2}+4x+2^{2}=-3+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=-3+4
Square 2.
x^{2}+4x+4=1
Add -3 to 4.
\left(x+2\right)^{2}=1
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{1}
Take the square root of both sides of the equation.
x+2=1 x+2=-1
Simplify.
x=-1 x=-3
Subtract 2 from 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}