Simply count up on both sides. Then take the number of increases between each y value and place it on top of the increase of the x value. Divide. To find the y-intercept, or "b", take the constant of the y and count back until the x is zero. For example, since the chart is consistently going up by 1s on each side, take the first "y" value, 3, and count one back to zero on the x. It is two.