1)
{x -y = 2
{2x-3y = -1
2)
{4x=-6y
{7y-2x=20
3)
{8x-3y =7
{3x+y=9

4)
{2(x+y) = -6
{3x-(x-y)=0

5)
{x+5y = -2
{0,5x-y=6



6)
{2x+3(x+y) = 11
{7(x+3y)-4y= -23