1) 1.2x+21-3.2x+12=2
-2x+33=2
-2x=2-33
-2x= -31
x= 31/2
2) 4.5*7/15х+4.5*2/9-0.77*8/11х+0.77*3/7= -1.75
3/10*7х+5/5-7/25*2х+11/100*3= -1.75
21/10х+1-14/25х+33/100= -1.75
105х-28х/50+1+33/100= -1.75
77х/50+1+33/100= -1.75
1.54х+100+33/100= -1.75
1.54х+133/100= -1.75
1.54х+1.33= -1.75
1.54х= -1.75-1.33
1.54х= -3.08
х= -2
1)96:3=32 (т)
2)78:2=39(в)
3)32+38=70 учеников
Ответ:70учеников
7х=100-9, 7х=91, х=91:7, х=13
26х=7+0.8, 26х=7.8, х= 7.8:26, х= 78:260, х= 0.3