(a) Find the slope of the tangent line to the parabola y = X2 + 7X at the point (3, 12) by using the following parameters. (0 The tangent line to the curve y = f(x) at the point P(a, f(a)) is the line through P with slope m = lim m: 5 X x>a f(X) - f(a) Xa provided that this limit exists