# Intermediate Algebra/Writing Linear Equations

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Linear equations have two variables: ${\displaystyle x}$ and ${\displaystyle y}$.

## Examples

${\displaystyle y=5+7x}$

${\displaystyle y=2-4x+4}$

${\displaystyle y=7/2-4x}$

If one were doing a walkathon and wanted to raise \$5 for every mile walked, an equation for the total money raised, ${\displaystyle y}$ as a function of the number of miles walked, ${\displaystyle x}$ would be ${\displaystyle y=5x}$. Would donors, however, promise to not only pay \$5 per mile but give an additional \$30 just for taking part, the equation would be ${\displaystyle y=5x+30}$. Note that this example is limited as negative miles don't make sense, but the line defined by the equation is infinite in either direction.