Your equation is y=-2x+5. First find the slope by plugging two points into the slope equation y2-y1 over x2-x1. This then gets you the slope of -2. Then find the point where x=0, which then gets you your y intercept or the b value in the equation. With the slope as m and y intercept as b, we can find that in the equation y=mx+b with the new values plugged in y=-2x+5.