2х-12+3х=5-х+1
5х+х=6+12
6х=18
х=18/6
х=3
1495,68....................
0,7×(34,1-18,4)+0,5×18,6-(9,8+1,6)×1,4=4,33
3/10=300г
5/100=50г
3/4=750г
3/5=600г
7÷7+(7-7)=1
7÷7+7÷7=2
(7+7+7)÷7=3
77÷7-7=4
(7+7)÷(-7)+7=5
(7×7-7)÷7=6
7+(7-7)×7=7
(7×7+7)÷7=8
(7+7)÷7+7=9
(77-7)÷7=10