Răspuns :

12. (21+14,4 +34,6 +x):4=29

70+x=116

x=116-70

x=46

13. (60+2x):2=47

60+2x=94

2x=34

x=17

(14+29+18+x+y):5=72

61+17+y=360

78+y=360

y=282