Answer

(a) The most complicated "inside" function is 6x + 4, so let

u = 6x + 4u' = 6

(b) First we change variables. We have to break up 30 into 5 ⋅ 6 so we can find u':

We use an appropriate pattern to integrate:

And finally put the original variable back in:

(u)⁵ + C = (6x + 4)⁵ + C

We conclude