Two lines are parallel if they have the same slope.

For the lines 2x-y+2=0 and x+y-4=0, the slope is :

2x - y + 2 = 0

=> y = 2x + 2

slope = 2

x + y - 4 = 0

=> y = -x - 4

slope = 1

**The two lines have different slopes, so they are not parallel.**