Logic Problems leaving me baffled.

[Stan Depain]

I have no idea how to achieve an answer to any of these questions.

For each set of premises, write a valid conclusion.

1)
~P -> Q
~P
________

2)
~M -> N
P -> ~N
________

3)
~A -> ~B
B
__________

4)
R v L
~L
_____

5)
W -> X
W
________


Now, I understand what all the symbols mean (conditional, etc), but I have no idea how to assign true or false values to these letters in order to figure out what letter answer to put down and whether or not that answer is false. I thought of performing truth tables, but I'm not necessarily sure how that would lead me to the answer I'm looking for. What am I failing to connect here?

 

[stapel]

1) You are given "If not-P, then Q" and "not-P". So they gave you the "if". Use the if-then to find the "then".

2) They gave you "If not-M, then N" and "If P, then not-N". See where contrapositives take you.

3) They gave you "If not-A, then not-B" and "B". Apply contrapositive to the if-then.

4) They gave you "R or L" and "not-L". If one of R and L has to be true, and L isn't true, then what is true?

5) They gave you "If W, then X" and "W". So they gave you the "if". Use the "if-then" to find the "then".

Eliz.