Răspuns :
E foarte simplu, ia le pe bucati si o sa stii sa faci si singur
![Vezi imaginea Justmeekarina](https://ro-static.z-dn.net/files/deb/e64e35e5d9657b878593f7dafb267f43.jpg)
a + b = 18
a = 5b
5b + b = 18
6b = 18
b = 18 : 6
b = 3
a = 5 * 3
a = 15
b ___/
a __/__/__/__/__/
18 : 6 = 3
b = 3
a = 3 * 5
a = 15
a = 5b
5b + b = 18
6b = 18
b = 18 : 6
b = 3
a = 5 * 3
a = 15
b ___/
a __/__/__/__/__/
18 : 6 = 3
b = 3
a = 3 * 5
a = 15