Solve for a
a=\frac{x+4}{2}
Solve for x
x=2\left(a-2\right)
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2a=x+8-4
Subtract 4 from both sides.
2a=x+4
Subtract 4 from 8 to get 4.
\frac{2a}{2}=\frac{x+4}{2}
Divide both sides by 2.
a=\frac{x+4}{2}
Dividing by 2 undoes the multiplication by 2.
a=\frac{x}{2}+2
Divide x+4 by 2.
x+8=2a+4
Swap sides so that all variable terms are on the left hand side.
x=2a+4-8
Subtract 8 from both sides.
x=2a-4
Subtract 8 from 4 to get -4.
Examples
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{ x } ^ { 2 } - 4 x - 5 = 0
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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
\lim _{x \rightarrow-3} \frac{x^{2}-9}{x^{2}+2 x-3}