Hello all, please help me

1.) Sketch the graph of function y=4x^3 - 8x^2-11x-3

I tried it, and got (x-3)(4x^2+4x+1) I can't factorise the quadratic to solve, need help

2.) (3w/2 - 5/4w)^3

Im clueless with this one i tried making the same common denominator, didnt help one bit, please provide explanation and full answers please.