2x(8x-1)-(4x-1)^2
4(3y-1)^2-18y(2y-1)

1) 2x(8x-1)-(4x-1)^2 = 16х^2-2х-(16х^2-8х+1)=  16х^2-2х-16х^2+8х-1=6х-1

2)  4(3y-1)^2-18y(2y-1) = 4(9у^2-6у+1) - 36у^2+18у =  36у^2-24у+4- 36у^2+18у= 4-6у