Partial fractions, indefinte integral

Hi, I have the problem:

http://webwork.csufresno.edu/webwork...54eb9ae4c1.png

and it states that the integrand has partial fractions decomposition:

http://webwork.csufresno.edu/webwork...836e2f37a1.png

So then I need to make $\displaystyle 7x^3+5x^2+125x+75=a(x)(x^2+25)+b(x^2)(cx+d)+(cx+d) (x^3)$

Now, would ax^3=7? I know what to do with simple A and B partial fractions but this is looking difficult especially when there is multiple variables multiplied by each other. How can I solve this?

Thanks,

Matt