Could you help me out on this question? If you could walk me through it, that would be great...

http://img508.imageshack.us/img508/2013/equationwd7.png

Substitute:
u = 1 + r^4
du = 4r^3 dr

Plug in (pulling out constants):
(9/4)*int[(u^(-1/4))du]

Integrate:
(3)*u^(3/4) + C

Plug back in for r:
(3)*(1+r^4)^(3/4) + C