4. Differentiate the following. Simplify your derivatives as much as possible. [10] a ) f(x) = (3x2 -4) b) y = (v x+ 2)x-2) c g x = (2x - 1)" and u = dy (x + 5) ? d) if y= - u +4 Vx+ x find u - 4 2 dx when x = 4