X+1/2y = 0 2x+y = 0 when both sides are multiplied by 2; When two expressions are subtracted, 2Y=4 Y=2 X=- 1.

2X=5[X+y], the right side moves to both sides of the left, and the two expressions are subtracted to get 2x- 10[x+y]=0, and X=-2 Y=6.