Solve for x
x=-1
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-4\left(-2\right)=x+9
Multiply both sides by -2, the reciprocal of -\frac{1}{2}.
8=x+9
Multiply -4 and -2 to get 8.
x+9=8
Swap sides so that all variable terms are on the left hand side.
x=8-9
Subtract 9 from both sides.
x=-1
Subtract 9 from 8 to get -1.
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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