2) 36+28x+21=393
28x=393-57
x=336/28
X=336
X=12
4) 70+b+6b=158
70+7b=158
7b=158-70
b=88/7
b=12,5
1) 8984/8-1123
2) 9386/2=4693
3) 907*9-852/3=7879
1. 907*9=8163
2. 852/3=284
3. 8163-284=7879
4) 840*6-795=4775
1. 840*6=5040
2. 795/3=265
3/ 5045-265=4775
5) 8*(739+564)=10424
1. 739+564=1303
2. 8*1303=10424
6) 9*(1010-235)=6975
1. 1010-235=775
2. 9*775=6975
97 – 88 – 39 + 42= 139-127=12