Solve for x
x=\frac{-y-21}{2}
Solve for y
y=-2x-21
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-2x-21=y
Swap sides so that all variable terms are on the left hand side.
-2x=y+21
Add 21 to both sides.
\frac{-2x}{-2}=\frac{y+21}{-2}
Divide both sides by -2.
x=\frac{y+21}{-2}
Dividing by -2 undoes the multiplication by -2.
x=\frac{-y-21}{2}
Divide y+21 by -2.
Examples
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{ x } ^ { 2 } - 4 x - 5 = 0
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y = 3x + 4
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Matrix
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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
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Limits
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