(5-1 1/3 - x ) * 27/31 = 3
5-4/3-х=3*31/27 11/3-х=31/9 х=2/9
1)4 3/3-1 1/3=3 2/3=11/3; 99/31-27/31х=3; -27/31х=3-99/31; -27/31х=-6/31; х=2/9.