[tex]\displaystyle\bf\\\left \{ {{3x-4y=18} \atop {5x+2y=4 \ |\cdot 2}} \right.\\\\\\+\left \{ {{3x-4y=18} \atop {10x+4y=8 }} \right. \\---------\\13x=26\\\\x=26:13\\\\\boxed{x=2}\\\\2y=4-5x=4-5\cdot 2=4-10=-6\\\\y=-6:2\\\\\boxed{y=-3}\\\\\\Otvet \ : \ (2 \ ; \ -3)[/tex]

Ответ:

(2; -3)

Объяснение:

{3х - 4у = 18 | : 2

{5х + 2у = 4

{1,5х - 2у = 9

{5х + 2у = 4

{6,5х = 13

{5х + 2у = 4

1)

6,5х = 13

х = 13 : 6,5

х = 2

2)

5х + 2у = 4

5 * 2 + 2у = 4

10 + 2у = 4

2у = 4 - 10

2у = -6

у = -6 : 2

у = -3