1) (x-2,3)-4 при х=1,5 ; (1,5-2,3)-4; 4-(-0,8)=4+0,8=4,8;
2) (3х + 1целая 4/15)+ 2/3 при х=1,2; (36/10+1 4/15)+2/3; (18/5+19/15)+2/3; (54/15+19/15)+2/3; 73/15+2/3; 73/15+10/15; 83/15; 5 целых 8/15
3) 11+( 3/8x - 5/6) при х=4,9; 11+(3/8*49/10-5/6); 11+(147/80-5/6); 11+(441/240-200/240);
11+241/240; 12 целых 1/240
4) 8/9+( 1/12x-7/9) при х= -4 ; 8/9+(-1/3-7/9);
8/9-10/9; -2/9