These problems are destroying my mind.

\int 1/((10x-3)^2)

So far I've... \int u^2 1/udu, u=10x-3

After this is where my thoughts unravel.

Maybe...

(1/10) * (u^3)/3 = (1/10) * ((10x-3)^3)/3 ????

The next one is

\int (6x+1) * \sqrt{3x^2+x}dx where u is given and u = 3x^2+x

I realize the derivative of 3x^2+x is 6x+1 and this offers some kind of portent but I fail to see the next logical step.

Any help is appreciated.