Solve for x
x=-3
x=3
Graph
Share
Copied to clipboard
3\left(x+2\right)^{2}+x^{2}-36=12\left(x+1\right)
Multiply both sides of the equation by 6, the least common multiple of 2,6.
3\left(x^{2}+4x+4\right)+x^{2}-36=12\left(x+1\right)
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(x+2\right)^{2}.
3x^{2}+12x+12+x^{2}-36=12\left(x+1\right)
Use the distributive property to multiply 3 by x^{2}+4x+4.
4x^{2}+12x+12-36=12\left(x+1\right)
Combine 3x^{2} and x^{2} to get 4x^{2}.
4x^{2}+12x-24=12\left(x+1\right)
Subtract 36 from 12 to get -24.
4x^{2}+12x-24=12x+12
Use the distributive property to multiply 12 by x+1.
4x^{2}+12x-24-12x=12
Subtract 12x from both sides.
4x^{2}-24=12
Combine 12x and -12x to get 0.
4x^{2}-24-12=0
Subtract 12 from both sides.
4x^{2}-36=0
Subtract 12 from -24 to get -36.
x^{2}-9=0
Divide both sides by 4.
\left(x-3\right)\left(x+3\right)=0
Consider x^{2}-9. Rewrite x^{2}-9 as x^{2}-3^{2}. The difference of squares can be factored using the rule: a^{2}-b^{2}=\left(a-b\right)\left(a+b\right).
x=3 x=-3
To find equation solutions, solve x-3=0 and x+3=0.
3\left(x+2\right)^{2}+x^{2}-36=12\left(x+1\right)
Multiply both sides of the equation by 6, the least common multiple of 2,6.
3\left(x^{2}+4x+4\right)+x^{2}-36=12\left(x+1\right)
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(x+2\right)^{2}.
3x^{2}+12x+12+x^{2}-36=12\left(x+1\right)
Use the distributive property to multiply 3 by x^{2}+4x+4.
4x^{2}+12x+12-36=12\left(x+1\right)
Combine 3x^{2} and x^{2} to get 4x^{2}.
4x^{2}+12x-24=12\left(x+1\right)
Subtract 36 from 12 to get -24.
4x^{2}+12x-24=12x+12
Use the distributive property to multiply 12 by x+1.
4x^{2}+12x-24-12x=12
Subtract 12x from both sides.
4x^{2}-24=12
Combine 12x and -12x to get 0.
4x^{2}=12+24
Add 24 to both sides.
4x^{2}=36
Add 12 and 24 to get 36.
x^{2}=\frac{36}{4}
Divide both sides by 4.
x^{2}=9
Divide 36 by 4 to get 9.
x=3 x=-3
Take the square root of both sides of the equation.
3\left(x+2\right)^{2}+x^{2}-36=12\left(x+1\right)
Multiply both sides of the equation by 6, the least common multiple of 2,6.
3\left(x^{2}+4x+4\right)+x^{2}-36=12\left(x+1\right)
Use binomial theorem \left(a+b\right)^{2}=a^{2}+2ab+b^{2} to expand \left(x+2\right)^{2}.
3x^{2}+12x+12+x^{2}-36=12\left(x+1\right)
Use the distributive property to multiply 3 by x^{2}+4x+4.
4x^{2}+12x+12-36=12\left(x+1\right)
Combine 3x^{2} and x^{2} to get 4x^{2}.
4x^{2}+12x-24=12\left(x+1\right)
Subtract 36 from 12 to get -24.
4x^{2}+12x-24=12x+12
Use the distributive property to multiply 12 by x+1.
4x^{2}+12x-24-12x=12
Subtract 12x from both sides.
4x^{2}-24=12
Combine 12x and -12x to get 0.
4x^{2}-24-12=0
Subtract 12 from both sides.
4x^{2}-36=0
Subtract 12 from -24 to get -36.
x=\frac{0±\sqrt{0^{2}-4\times 4\left(-36\right)}}{2\times 4}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 4 for a, 0 for b, and -36 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\times 4\left(-36\right)}}{2\times 4}
Square 0.
x=\frac{0±\sqrt{-16\left(-36\right)}}{2\times 4}
Multiply -4 times 4.
x=\frac{0±\sqrt{576}}{2\times 4}
Multiply -16 times -36.
x=\frac{0±24}{2\times 4}
Take the square root of 576.
x=\frac{0±24}{8}
Multiply 2 times 4.
x=3
Now solve the equation x=\frac{0±24}{8} when ± is plus. Divide 24 by 8.
x=-3
Now solve the equation x=\frac{0±24}{8} when ± is minus. Divide -24 by 8.
x=3 x=-3
The equation is now solved.
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}