I used a karnaugh map to find the minimal representation of this:

x'y'z + x'y'z' + x'yz'

........xy......xy'.....x'y'....x'y.....

z.......0........0........1......0.....

z'.......0........0........1.....1.....

so my minimal representation is

x'y' + x'z'

is this ok?