Assuming you mean:
2x + 2y = 26
-3x + 3y = -21
multiply the top equation by 3 on both sides and the bottom equation by 2 on both sides
6x + 6y = 78
-6x + 6y = -42
add the two equations straight down
0x + 12y = 36
divide by 3 on both sides
0x + y = 12
y = 12
back to the equations:
6x + 6y = 78
-6x + 6y = -42
multiply the bottom equation by -1 on both sides
6x + 6y = 78
6x - 6y = 42
add the two equations together
12x + 0y = 120
divide both sides by 12
x + 0y = 10
x = 10
Answer: x = 10, y = 12