2(7x+y)-3(5x-y)=x+y
3(9x-2y)+4(7x+4y)=8(x+y)+4
14x+2y-15x+3y=x+y
27x-6y+28x+16y=8x+8y+4
14x+2y-15x+3y-x-y=0
27x-6y+28x+16y-8x-8y=4
-2x+4y=0
47x+2y=4
1) -2x+4y=0
4y=0+2x
y=0+0,5x
2)47x+2(0+0,5x)=4
47x+0+x=4
48x=4-0
48x=4
x=1/12
если x=1/12
y=-2*1/12+4y=0
-6+4y=0
4y=6
y=3/2
(1/12; 3/2)