1) 3(х+4)+6(11-х)=9;
3х+12+66-6х=9;
3х-6х=9-12-66;
-3х=-69;
х=23.
2) 8(1-х)+5(х-2)=2;
8-8х+5х-10=2;
-8х+5х=2+10-8;
-3х=4;
х=-4/3;
х=-1целая1/3.
3) 7(4-t)+3(t-5)=9t;
28-7t+3t-15=9t;
-7t+3t-9t=15-28;
-13t=-23;
t=1целая10/23.
4) 3(х+1,5)+2(3+х)=-5;
3х+4,5+6+2х=-5;
3х+2х=-5-6-4,5;
5х=-15,5;
х=-3,1.