((y+1)/(y-1)-y/(y+1))*(3y+1)/(y²+y)=((y+1)²-(y²-y)/(y²-1))*(3y+1)/(y²+y)=
=((y²+2y+1-y²+y)/(y²-1))*(3y+1)/(y²+y)=((3y+1)/(y²-1))*(3y+1)/(y²+y)=
=(3y+1)²/((y-1)(y+1)*y*(y+1))=(3y+1)²/(y*(y+1)²*(y-1)).
(m³ * m²)² * (2m)³ = (m³⁺²)² * 8m³ =(m⁵)² * 8m³ = m¹⁰ * 8m³ = 8m¹⁰⁺³ = 8m¹³