2.Determine the second derivative of each of the following: \text { a. } y=7 x^{2}-9 x+22 \text { b. } f(x)=-9 x^{5}-4 x^{3}+6 x-12 \text { c. } y=5 x^{-3}+10 x^{3} \text { d. } f(x)=(4 x-8)^{3}