For the integral, (a) identify u and u' and (b) integrate by substitution.
(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