{x=6-4y

{3x-y=8

3(6-4y)-y=8

y=10/13

x=6-4*10/13

x=38/13

{38/13+4*10/13=6

{3*38/13-10/13=8

6=6

8=8

(7x+3y)+(4x-3y)=43+67

11x=110

x=10

7(10)+3y=43

y=-9

ответ x=10 y=9