A method of graphing a linear equation uses the Y-Intercept and the slope to create a line. Use a third point to check your work.

For example, if you want to plot $ f(x)=2x+1 $, the Y-intercept is to calculate $ f(0)=1 $ which is the height of the function at cero. The slope is the coefficient that multiply x, which in this case is 2. A third point could be evaluate at $ x=1 $ to obtain $ f(1)=3 $. So you have two positions in the cartesian plane: $ (0,1) $ and $ (1,3) $, which determine an unique line of slope 2.
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