Răspuns :
a + b = 63
a : b = 2 rest 9
a = 2b + 9
2b + 9 + b = 63
3b = 54
b = 54 : 3
b = 18
a = 63 - 18
a = 45
a : b = 2 rest 9
a = 2b + 9
2b + 9 + b = 63
3b = 54
b = 54 : 3
b = 18
a = 63 - 18
a = 45