a$)$ Are the following argument forms valid? Write out the symbolic representation of the argument forms, and, finally, name the ar$-$ gument forms.

$(1)$

No hair $->$ Bald

Bald

$$ No hair

$(2)$

No hair $->$ Bald

Hair

$$ Not bald

B$)$ Consider the following definition:

Baldness is equivalent to no hair. That is$,$ we have the bi$-$conditional statement,

Bald $->$ No hair.

With the above definition only now in mind, do the argument forms above change in their validity? Justify your answer via truth tables and identify the critical rows.

c$)$Show that the following argument form is valid by deducing the conclusion from the premises using the rules of inference $($i$.$e$.,$ sim$-$ ple valid argument forms$).$ Give reasons for each step. DO NOT USE A TRUTH TABLE

$1)$ p$$q

$2)($q$)$r

$3)($p$$s$)$t $4)$ r

$5)$ q $->$ u $$ s $6)$ t