((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)).
1) 10,5+ 9,5= 20 км/ ч общая скорость
2) 48: 20=2,4 ч = 160 мин
1) 2-0,007= 1,993 м/с скорость 2 жука
2) 1,993+0,004= 1,997 м/с общая скорость
3) 1,997×30= 59,91см = 0,5991 м
4a(4c-8) = 16ac-32a
16ab(3c-6) = 48abc-96