1,8(5/9z-0.8)-1.2(5/6+0.4)=1.8*5/9z-1.8*0.8-1.2*5/6-1.2*0.4=z-1.44-1-0.48=z-2.92
1,8(5/9z-0,8) - 1,2(5/6+0,4)=1,8*5/9z -1,8*0,8 - 1,2*5/6 - 1,2*0,4 = z - 1,44 - 1 - 0,48 = z - 2,92