Question 189542
It helps if you know the rules by heart (ie understand what they truly mean).


<pre>
1. C -> (T -> L)
2. ~L
3. ~E -> C
4. L v ~E /~T
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5.  ~E                  4,2   Disjunctive Syllogism
6.  C                   3,5   Modus Ponens
7.  T -> L              1,6   Modus Ponens
8.  ~T                  7,2   Modus Tollens
</pre>