4)Determine if the argument is valid or invalid. (Hint: The easiest way to do this is to either use truth tables or a proof.) Premises:

-q=>-p

q=>-r

s=>r

-s=>t

Conclusion: p=>t

Valid?

Invalid ?

5)True or false, when formulating a direct proof of the argument below you must replace a proposition with it's contrapositive.

q=>r

r=>-s

-s=>-s

Conclusion: q=>-t

true or false?

6)

True or False. When formulating an indirect proof of the argument below, you will need use the Law of Syllogism. Premises:

If Danny is a good math student then he will do well on the test. Danny did not do well on the test.

Conclusion:

Danny is not a good math student

True or false?

7)True or False. When formulating a direct proof of the argument below, you will need to replace the conditional with its contrapositive.

Premises:

q=>r

-r

conclusion:-q

true or false?

True or False. When formulating an indirect proof of the argument below, you will need to assume that r is true and prove that p is false. Premises:-q=>r

s=>-q

-p=>s

sp

conclusion:

r

true or false?

3)Determine if the argument is valid or invalid. (Hint: The easiest way to do this is to either use truth tables or a proof.)

Premises:

p=>-q

-q=>r

conclusion:

q=>r

valid?

invaid?