3) 10+5(x-5y)=6(x-4y),\\ 2x + 3(y + 5) = - 5 - 2(y - 2x) ;

3. 10+5(x-5y)=6(x-4y), 2x + 3(y + 5) = - 5 - 2(y - 2x) :

4. 10+5(x-5y)=6(x-4y) → 5x - 25y + 10 = 6x - 24y → x = y - 10

2x + 3(y + 5) = - 5 - 2(y - 2x) → 2x + 3y + 15 = -5 - 2y + 4x → -2x + 5y = -20