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-\frac{3x}{x+4}
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-\frac{3x}{x+4}
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\frac{\left(4x-x^{2}\right)\times 3}{x^{2}-16}
Divide 4x-x^{2} by \frac{x^{2}-16}{3} by multiplying 4x-x^{2} by the reciprocal of \frac{x^{2}-16}{3}.
\frac{3x\left(-x+4\right)}{\left(x-4\right)\left(x+4\right)}
Factor the expressions that are not already factored.
\frac{-3x\left(x-4\right)}{\left(x-4\right)\left(x+4\right)}
Extract the negative sign in 4-x.
\frac{-3x}{x+4}
Cancel out x-4 in both numerator and denominator.
\frac{\left(4x-x^{2}\right)\times 3}{x^{2}-16}
Divide 4x-x^{2} by \frac{x^{2}-16}{3} by multiplying 4x-x^{2} by the reciprocal of \frac{x^{2}-16}{3}.
\frac{3x\left(-x+4\right)}{\left(x-4\right)\left(x+4\right)}
Factor the expressions that are not already factored.
\frac{-3x\left(x-4\right)}{\left(x-4\right)\left(x+4\right)}
Extract the negative sign in 4-x.
\frac{-3x}{x+4}
Cancel out x-4 in both numerator and denominator.
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}