# Section 2.1: Problem 10 Solution

Working problems is a crucial part of learning mathematics. No one can learn... merely by poring over the definitions, theorems, and examples that are worked out in the text. One must work part of it out for oneself. To provide that opportunity is the purpose of the exercises.

James R. Munkres

Rewrite each of the following wffs in a way which explicitly lists each symbol in the actual order:

(a)
.

(b)
.

In each case, say which variables occur free in the wff.

(a)
(we used extra parentheses for readability),
is free variables.

(b)
(same here),
and
are free variables.