А) 0.2(5y - 2) = 0.3(2у-1) - 0.9
у-0,4=0,6у-0,3-0,9
у-0,4=0,6у-1,2
у-0,6у=-1,2+0,4
0,4у=-0,8
у=-0,8/0,4=2
б) (4 1/6у + 11 1/4) : 4/15 = 2/3у + 5 2/3
4 1/6у + 11 1/4 = (2/3у + 5 2/3)*4/15
4 1/6у + 11 1/4 = (2/3у + 17/3)*4/15
4 1/6у + 11 1/4 = 4/15*2/3у + 4/15*17/3
4 1/6у+11 1/4=8/45у+68/45
4 1/6у+11 1/4=8/45у+1 23/45
4 1/6у-8/45у=1 23/45-11 1/4
4 15/90у-16/90у=1 92/180-11 45/180
3 15/90у-16/90у=92/180-10 45/180
3у-1/90у=47/180-10
2 89/90у=-9 133/180
269/90у=-1753/180
у=-1753/180 :269/90=-1753/180 *90/269=-1753/2*1/269=-1753/538=-3 139/538