Răspuns :
5 a + 15 b + 10 z = 30
5 × ( a + 3 b + 2 z ) = 30
a + 3 b + 2 z = 30 : 5
a + 3 b + 2 z = 6 → inmultesc relatia cu 3
3 × a + 3 × 3 b + 3 ×2 z = 3 × 6
3 a + 9 b + 6 z = 18
5 a + 15 b + 10 z = 30
5 × ( a + 3 b + 2 z ) = 30
a + 3 b + 2 z = 30 : 5
a + 3 b + 2 z = 6 → inmultesc relatia cu 3
3 × a + 3 × 3 b + 3 ×2 z = 3 × 6
3 a + 9 b + 6 z = 18