Solving Equations in Quadratic Form

Hi I'm kinda confused by these equations.

1.) 3[ (x+3) / (2x-1) ]^2 - 4(x+3) / (2x-1) + 1 = 0

2.) 36x^4/3 - 25x^2/3 + 4 = 0

Thanks!

3
= { replacing x }
=
=
=
=

Or {subtituting by a}
Or
Or
Or (4a-1)(9a-4)=0
Or
Or
Or
Or

You're welcome!