b g(b) Use the Substitution Formula, f(g(x)) . g'(x) dx = f(u) du where g(x) = u, to evaluate the following integrals. a g(a) a . 13 ( 4 + 1 4 ) 3 at b. +3 (4 + + 4 ) 3 at - 1 . . . a. 13 ( 4 + 1 4 ) ' at = (Simplify your answer.) b. 13 ( 4 + 1 4 ) ' at = (Simplify your answer.)