NEED HELP

I'm trying to help my sister with this problem and don't know where to start, any suggestions?

x - 1 + y - 1 =

a. (xy + 1)/y
b. (x + y)/(x - y)
c. (1 - xy)/y
d. (1 - xy)/x
e. (xy + 1)/x
f. (x + y)/xy
g. none of these

Thanks RUTHIE!

All of the answers have denominators, and the original expression didn't, so I don't see how any of the answers (a) through (f) could be correct.

Eliz.

Thanks ELIZ you are awesome!