Răspunsuri

2014-11-18T19:34:13+02:00
2014-11-18T19:39:05+02:00
7a+2=4a+17
7a-4a=17-2
3a=15
a=15:3
a=5
Verificare:
7x5+2=4x5+17
35+2=20+17
37=37 (A)