Răspuns :
Daca sunt proportionala asta inseamna ca x/y=2/3 adica 2y=3x
Dar x-y=15 adica x=15+y Inlocuim in prima ecuatie.
2y=3(15+y) ⇔ 2y = 45 +3y | -2y ⇔ 0 = 45+y ⇒y=-45 Ne ducem in x-y=15 ⇒ x = 15-45= -30
Dar x-y=15 adica x=15+y Inlocuim in prima ecuatie.
2y=3(15+y) ⇔ 2y = 45 +3y | -2y ⇔ 0 = 45+y ⇒y=-45 Ne ducem in x-y=15 ⇒ x = 15-45= -30