sometimes true.
For example if x=2 and y=5
You’d substitute 5 in for y, 5-3 and you’d get 2.
That would make x and y equal to one another
But if x=2 and y=4 and you substitute in the values 4-3=1 and they would not be equal.
It all depends on the x and y value, but sometimes it may be true.