#1
{2x+3y=10
{x-2y=-9|*2
-{2x+3y=10
-{2x-4y=-18
7y=28|:7
y=4
2x+12=10
2x=10-12
2x=-2|:2
x=-1
#2
{2x-5y=9|*2
{4x+2y=6
-{4x-10y=18
-{4x+2y=6
-12y=12|:(-12)
y=-1
4x-2=6
4x=6+2
4x=8|:4
x=2
#3
{3(2x+y)-26=3x-2y
{15-(x-3y)=2x+5
{6x+3y-26=3x-2y
{15-x+3y=2x+5
{6x+3y-3x+2y=26
{-x+3y-2x=5-15
+{3x+5y=26
+{-3x+3y=-10
8y=16|:8
y=2
3x+10=26
3x=26-10
3x=16|:3
x=5 1/3