Question 147503
symbolize the following argument and then use a truth table to determine whether the argument is valid or invalid.
1.  Valerie will go out if and only if she does not have homework.
    Valerie did not go out
    Therefore, Valerie had homework.

p= (for me) Valerie will go out   q= She does not have homework.

premise 1 p<-->q         premise 2 = p'    conclusion q'
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[(p<-->q) and p']---> q'
..T..T.T...F..F....T..F
..T..F.T...F..F....T..F
..F..F.F...F..T....T..T
..F..T.F...T..T....T..T

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It is a valid argument; it is True under all conditions for p and q
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Cheers,
Stan H.
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