finding MGU for symmetrical expression

Question

given this pair of expressions, is it possible to find a MGU for it?

1. f(x,y)
2. f(y,x)

I wanted to say that it is possible, when x/y, but I wasn't sure if that's legal. what do you guys say?

thanks!

Answer 1

Yes, these terms can be easily unified, producing the assertion x=y as a side effect.