The slope of a line is found by taking the difference in y divided by the difference in x. For the point they give us that's (3-1)/(2-(-2)) = 2/4 = 1/2 A line will be perpendicular to another line if their slopes are negative reciprocals of each other. So we want a line whose slope is -2. Setting up the slope equation with the y in place gives (0-y)/(1-(-1)) = (-y)/2 We need this to equal -2 -y/2=-2 -y = -4 y = 4
