Evaluate
9\left(x^{2}-4y^{2}\right)
Expand
9x^{2}-36y^{2}
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\left(9\left(-x\right)+18y\right)\left(-x-2y\right)
Use the distributive property to multiply 9 by -x+2y.
9\left(-x\right)^{2}-18\left(-x\right)y+18y\left(-x\right)-36y^{2}
Apply the distributive property by multiplying each term of 9\left(-x\right)+18y by each term of -x-2y.
9x^{2}-18\left(-x\right)y+18y\left(-x\right)-36y^{2}
Calculate -x to the power of 2 and get x^{2}.
9x^{2}+18xy+18y\left(-x\right)-36y^{2}
Multiply -18 and -1 to get 18.
9x^{2}+18xy-18yx-36y^{2}
Multiply 18 and -1 to get -18.
9x^{2}-36y^{2}
Combine 18xy and -18yx to get 0.
\left(9\left(-x\right)+18y\right)\left(-x-2y\right)
Use the distributive property to multiply 9 by -x+2y.
9\left(-x\right)^{2}-18\left(-x\right)y+18y\left(-x\right)-36y^{2}
Apply the distributive property by multiplying each term of 9\left(-x\right)+18y by each term of -x-2y.
9x^{2}-18\left(-x\right)y+18y\left(-x\right)-36y^{2}
Calculate -x to the power of 2 and get x^{2}.
9x^{2}+18xy+18y\left(-x\right)-36y^{2}
Multiply -18 and -1 to get 18.
9x^{2}+18xy-18yx-36y^{2}
Multiply 18 and -1 to get -18.
9x^{2}-36y^{2}
Combine 18xy and -18yx to get 0.
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}