Answer:
(-1;-3)
Step-by-step explanation:
[tex]\left \{ {{4(2x+y)=4*(-5)} \atop {3x-4y=9}} \right. \ => \ \left \{ {{8x+4y=-20} \atop {3x-4y=9}} \right. \ => \ \left \{ {{11x=-11} \atop {2x+y=-5}} \right. \ => \ \left \{ {{x=-1} \atop {y=-3}} \right.[/tex]
