A.12:3-2=12:1=12;
12:3-2=4-2=2
B.(198-2x99):198+1= 0:199=199
(198-2x99):198+1=0:198+1=1
C. 18x2+1=18x3=54
18x2+1=36+1=37
D. 15+2:2+15=17:17=1
15+2:2+15=15+1+15=31
2.Afla numerele a si b din egalitatile
[(a+116:2)x3+4]x11=1991
(a+116:2)x3+4=1991:11
(a+116:2)x3=181-4
a+58=177
a=177-58
a=119
(b:11-4):3-110:2=4
(b:11-4):3-55=4
(b:11-4):3=4
+55
(b:11-4):3=59
b:11-4=59*3
b:11-4=177
b:11=177+4
b=181*11
b=1991