To find the slope, you need to subtract 4 from 13 and 0 from 3. So this will look like 9/3, which would be 3. To find the y-intercept, plug in one of the coordinates, so let's take (0, 4) since it's easier. If you plug in the 0 as the x and the 4 as the y in the equation, it should look like, 4 = 3(0) + b. 0 times 3 is 0, so that makes the b (y-intercept) 4.
