the equation of a line in slope- intercept form isy = mx + c ( m is the slope and c the y-intercept )y = - 2x + 2 is in this form with slope m = - 2given a line with slope m then the slope of a line perpendicular to it is = - = - = the point (0, 1 ) is the y- intercept ⇒ c = 1y = x + 1 ← equation of perpendicular line