The y-intercept of A is 7. A also passes through point (7, 2). (a) Find an equation of A in the form y = mx + c. (b) B is perpendicular to A and also has a y-intercept of 7. Write down the equation for B in the form y = mx + c.

(a) y-intercept = (0,7); other point = (7,2) ; gradient, m = change in y / change in x ; m = (0 - 7) / (7 - 2) => m = -7/5 ; y = mx + c (we know from the question that c=7) ; y = (-7/5)x + 7(b) gradient of B is -1/(-7/5) = 5 / 7 ; y = (5/7)x + 7