Solve for x
x=-4
x=2
Graph
Share
Copied to clipboard
x^{2}+7x+12+\left(x-2\right)\left(x-1\right)=30
Use the distributive property to multiply x+3 by x+4 and combine like terms.
x^{2}+7x+12+x^{2}-3x+2=30
Use the distributive property to multiply x-2 by x-1 and combine like terms.
2x^{2}+7x+12-3x+2=30
Combine x^{2} and x^{2} to get 2x^{2}.
2x^{2}+4x+12+2=30
Combine 7x and -3x to get 4x.
2x^{2}+4x+14=30
Add 12 and 2 to get 14.
2x^{2}+4x+14-30=0
Subtract 30 from both sides.
2x^{2}+4x-16=0
Subtract 30 from 14 to get -16.
x=\frac{-4±\sqrt{4^{2}-4\times 2\left(-16\right)}}{2\times 2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 2 for a, 4 for b, and -16 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-4±\sqrt{16-4\times 2\left(-16\right)}}{2\times 2}
Square 4.
x=\frac{-4±\sqrt{16-8\left(-16\right)}}{2\times 2}
Multiply -4 times 2.
x=\frac{-4±\sqrt{16+128}}{2\times 2}
Multiply -8 times -16.
x=\frac{-4±\sqrt{144}}{2\times 2}
Add 16 to 128.
x=\frac{-4±12}{2\times 2}
Take the square root of 144.
x=\frac{-4±12}{4}
Multiply 2 times 2.
x=\frac{8}{4}
Now solve the equation x=\frac{-4±12}{4} when ± is plus. Add -4 to 12.
x=2
Divide 8 by 4.
x=-\frac{16}{4}
Now solve the equation x=\frac{-4±12}{4} when ± is minus. Subtract 12 from -4.
x=-4
Divide -16 by 4.
x=2 x=-4
The equation is now solved.
x^{2}+7x+12+\left(x-2\right)\left(x-1\right)=30
Use the distributive property to multiply x+3 by x+4 and combine like terms.
x^{2}+7x+12+x^{2}-3x+2=30
Use the distributive property to multiply x-2 by x-1 and combine like terms.
2x^{2}+7x+12-3x+2=30
Combine x^{2} and x^{2} to get 2x^{2}.
2x^{2}+4x+12+2=30
Combine 7x and -3x to get 4x.
2x^{2}+4x+14=30
Add 12 and 2 to get 14.
2x^{2}+4x=30-14
Subtract 14 from both sides.
2x^{2}+4x=16
Subtract 14 from 30 to get 16.
\frac{2x^{2}+4x}{2}=\frac{16}{2}
Divide both sides by 2.
x^{2}+\frac{4}{2}x=\frac{16}{2}
Dividing by 2 undoes the multiplication by 2.
x^{2}+2x=\frac{16}{2}
Divide 4 by 2.
x^{2}+2x=8
Divide 16 by 2.
x^{2}+2x+1^{2}=8+1^{2}
Divide 2, the coefficient of the x term, by 2 to get 1. Then add the square of 1 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}+2x+1=8+1
Square 1.
x^{2}+2x+1=9
Add 8 to 1.
\left(x+1\right)^{2}=9
Factor x^{2}+2x+1. 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+1\right)^{2}}=\sqrt{9}
Take the square root of both sides of the equation.
x+1=3 x+1=-3
Simplify.
x=2 x=-4
Subtract 1 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}