Using the y=mx+b format, m is the slope which is -1/2. I got this by doing rise over run. Since you have go down once, and right twice, the slope is -1/2. b is the y-intercept, or the point at which the line hits the y axis when x is 0. The intercept lies at -3.5. Hence the equation for this line is y = -1/2x - 3.5
