1)2x-y=2

3x+y=8

2x-y+3x+y=2+8

5x=10

x=2

2×2-y=2

4-y=2

-y=-2

y=2

(2;2)

2)4x-3y=3

4x-7y=-5

4x-3y-4x+7y=3+5

4y=8

y=2

4x-3×2=3

4x-6=3

4x=9

x=9/4=2 1/4

(2 1/4;2)

3)7x+3y=-1

3x-7y=17

7x=-1-3y

3x-7y=17

x=-1/7-3y/7

3x-7y=17

x=-1/7-3y/7

3×(-1/7-3y/7)-7y=17

x=-1/7-3y/7

y=-61/29

x=-1-3×(-61/29)=22/29

y=-61/29

(22/29,-61/29)