You can find the y-intercept by looking at the graph and seeing which point crosses the y axis. This point will always have an x coordinate of zero. The formula for slope is sometimes referred to as "rise over run", because the fraction onsists of the "rise" (being the change in y, going up or down) divided by the "run" (being the change in x, going from left to the right).
You would keep the 2 hour for the whole number of the mixed number and then, make the minutes (15) as a fraction with 60, and divide them both by 20. that is just for the mixed number.
