(a) Find the slope m of the tangent to the curve y = 9 + 5x2 − 2x3 at the point where x = a (b) Find equations of the tangent lines at the points (1, 12) and (2, 13). (i) y(x)= (at the point (1, 12)) (ii) y(x)= (at the point (2, 13))