1
(8y²+2y)/(2y-1)(4y²+2y+1)-(2y-1)/(4y²+2y+1)=
=(8y²+2y-4y²+1)/(2y-1)(4y²+2y+1)=(4y²+2y+1)/(2y-1)(4y²+2y+1)=1/(2y-1)
2
1+(2y+1)/2y-(4y²+10y)/2y(2y+1)=(4y²+2y+4y²+4y+1-4y²-10y)/2y(2y+1)=
=(4y²-4y+1)/2y(2y+1)=(2y-1)²/2y(2y+1)
3
1/(2y-1)*(2y-1)²/2y(2y+1)=(2y-1)/2y(2y+1)
4
(2y-1)/2y(2y+1):1/2y=(2y-1)/2y(2y+1) *2y=(2y-1)/(2y+1)