1.{x-y=2|*2
2x-3y=-1
{2x-2y=4
2x-3y=-1
{x-y=2
5y=5|:5
{x-y=2
y=1
{x-1=2
y=1
{x=3
y=1
2. {-x+y=4
4x+y=-1
{-x+y=4
-5x=5|:-5
{-x+y=4
x=1
{-1+y=4
x=1
{y=5
x=1
3. {3x+y=4
5x+y=10
{3x+y=4
-2x=-6|:-2
{3x+y=10
x=3
{9+y=10
x=3
{y=10
x=3
4. {8x-3y=7
3x+y=9|*3
{8x-3y=7
9x+3y=27
{8x-3y=7
17x=34|:17
{8x-3y=7
x=2
{16-3y=7
x=2
{3y=9
x=2
{y=3
x=2
5. {x+5y=-2
0,5x-y=6|*2
{x+5y=-2
x-2y=12
{x+5y=-2
7y=-14|:7
{x+5y=-2
y=-2
{x+(-10)=-2
y=-2
{x=8
y=-2
6. {12x-y=18
x+0,5y=5|*2
{12x-y=18
2x+y=10
{14x=28|:14
2x+y=10
{x=2
4+y=10
{x=2
y=6