Evaluate
\left(x-4\right)\left(-x^{2}+4x-5\right)
Expand
20-21x+8x^{2}-x^{3}
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\left(-x^{2}\right)x-4\left(-x^{2}\right)+4x^{2}-21x+20
Use the distributive property to multiply -x^{2}+4x-5 by x-4 and combine like terms.
\left(-x^{2}\right)x+4x^{2}+4x^{2}-21x+20
Multiply -4 and -1 to get 4.
\left(-x^{2}\right)x+8x^{2}-21x+20
Combine 4x^{2} and 4x^{2} to get 8x^{2}.
-x^{3}+8x^{2}-21x+20
To multiply powers of the same base, add their exponents. Add 2 and 1 to get 3.
\left(-x^{2}\right)x-4\left(-x^{2}\right)+4x^{2}-21x+20
Use the distributive property to multiply -x^{2}+4x-5 by x-4 and combine like terms.
\left(-x^{2}\right)x+4x^{2}+4x^{2}-21x+20
Multiply -4 and -1 to get 4.
\left(-x^{2}\right)x+8x^{2}-21x+20
Combine 4x^{2} and 4x^{2} to get 8x^{2}.
-x^{3}+8x^{2}-21x+20
To multiply powers of the same base, add their exponents. Add 2 and 1 to get 3.
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}