Evaluate
\left(a-4b\right)\left(5b+9\right)
Expand
5ab+9a-20b^{2}-36b
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5ba-20b^{2}+9\left(-4b+a\right)
Use the distributive property to multiply 5b by a-4b.
5ba-20b^{2}-36b+9a
Use the distributive property to multiply 9 by -4b+a.
5ba-20b^{2}+9\left(-4b+a\right)
Use the distributive property to multiply 5b by a-4b.
5ba-20b^{2}-36b+9a
Use the distributive property to multiply 9 by -4b+a.
Examples
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{ x } ^ { 2 } - 4 x - 5 = 0
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4 \sin \theta \cos \theta = 2 \sin \theta
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y = 3x + 4
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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.
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\frac { d } { d x } \frac { ( 3 x ^ { 2 } - 2 ) } { ( x - 5 ) }
Integration
\int _ { 0 } ^ { 1 } x e ^ { - x ^ { 2 } } d x
Limits
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