Solve for y
y=\frac{x-9}{4}
Solve for x
x=4y+9
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-4y=9-x
Subtract x from both sides.
\frac{-4y}{-4}=\frac{9-x}{-4}
Divide both sides by -4.
y=\frac{9-x}{-4}
Dividing by -4 undoes the multiplication by -4.
y=\frac{x-9}{4}
Divide 9-x by -4.
x=9+4y
Add 4y to both sides.
Examples
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{ x } ^ { 2 } - 4 x - 5 = 0
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4 \sin \theta \cos \theta = 2 \sin \theta
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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