15. Let f(x)be a continuous function with f(4)=3, f'(4)=5 and f"(4)=-9. a) Find the equation of the tangent line to A(x)=2f(x)+7 at x=4. 2 X b) Is g(x)= J(x) ) Find k'(2) where k(x)=f(x) . d) Find m'(4) where m(x)=e/". e) Is j(x)=(f (x))2 concave up or concave down at x =4 ? increasing or decreasing at x =47