Question 37187
To use the point-slope form, y - y1 = m(x - x1), you need a point AND the slope.  The slope needs to be found in the usual way...m = (y2 - y1)/(x2 - x1) = (-2 - 0)/(2 - 0) = -1.  NOW plug into the form above and get y - (-2) = (-1)(x - 2)  and finally y = -x.