Daca 15a-10b=75,afla 3a-2b.

Răspuns :

15 a - 10 b = 75

5 × ( 3 a - 2 b ) = 75

3 a - 2 b = 75 : 5

3 a - 2 b = 15

15a-10b=75 | ÷5
3a-2b=15