I like saying rise over run because it helps me remember that rise means how many units you move up or down from point to point which on a graph would be a change in the y values. Also that run means how far left or right you move from point to point which on the graph would mean a change of x values.
We will use the equation: r t = 3/4 r ( t+12 ) /:r t = 3/4 t + 9 t - 3/4 t = 9 1/4 t = 9 t = 9 * 4 = 36 minutes ( takes a trip to the market ) 36 + 12 = 48 minutes The ride home takes 48 minutes.
