The parenthesis are not necessary, since 'or' is associative, so we have:
F = XYZ + X' + Z'
So the K-map would look something like:
XY XY' X'Y X'Y'
+---+---+---+---+
Z | | | | |
+---+---+---+---+
Z' | | | | |
+---+---+---+---+
We start out with the XYZ
term, which occupies only one square since it fixes the value of all three variables:
XY XY' X'Y X'Y'
+---+---+---+---+
Z | T | | | |
+---+---+---+---+
Z' | | | | |
+---+---+---+---+
Then X'
touches one half of the table:
XY XY' X'Y X'Y'
+---+---+---+---+
Z | T | | T | T |
+---+---+---+---+
Z' | | | T | T |
+---+---+---+---+
And finally Z'
touches the bottom row, and only XY'Z
is left as false:
XY XY' X'Y X'Y'
+---+---+---+---+
Z | T | F | T | T |
+---+---+---+---+
Z' | T | T | T | T |
+---+---+---+---+