2(3х-11)/8 - (3-5х)/8= 4(х+6)/8
2(3х-11)-(3-5х)=4(х+6)
6х-22-3+5х=4х+24
6х+5х-4х=24+22+3
7х=49
х=7
450 +а = 920 - 40
450 + а =880
а =880 - 450
а =430
проверка: 450 + 430 =920 - 40
880 =880
14/15*10/49+5 3/7=118;
1 2/3*14/15*5/7=10/9;
1/3*6/7-1/7*3/4=105;
(1-3/4)*(4/5-3/4)=1/80;
1 3/11-27/44*4/9=1
1) 9*4=36
2)36:6=6
каждая получила по 6 пятёрок