Solve for x
x=30
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84-x-\left(-3\right)-x=x-3
To find the opposite of x-3, find the opposite of each term.
84-x+3-x=x-3
The opposite of -3 is 3.
87-x-x=x-3
Add 84 and 3 to get 87.
87-2x=x-3
Combine -x and -x to get -2x.
87-2x-x=-3
Subtract x from both sides.
87-3x=-3
Combine -2x and -x to get -3x.
-3x=-3-87
Subtract 87 from both sides.
-3x=-90
Subtract 87 from -3 to get -90.
x=\frac{-90}{-3}
Divide both sides by -3.
x=30
Divide -90 by -3 to get 30.
Examples
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Linear equation
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.
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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