Solve for x
x=5
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81-8x-7x=6
Subtract 7x from both sides.
81-15x=6
Combine -8x and -7x to get -15x.
-15x=6-81
Subtract 81 from both sides.
-15x=-75
Subtract 81 from 6 to get -75.
x=\frac{-75}{-15}
Divide both sides by -15.
x=5
Divide -75 by -15 to get 5.
Examples
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{ x } ^ { 2 } - 4 x - 5 = 0
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Linear equation
y = 3x + 4
Arithmetic
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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.
Differentiation
\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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