Dual = "The dual of a compound proposition that contains only the logical operators ∨, ∧, and ¬ is the compound proposition obtained by replacing each ∨ by ∧, each ∧ by ∨, each T by F, and each F by T. The dual of s is denoted by s∗."
we don't negate any of the literal.
Answer:
a) p$\vee$∼q$\vee$∼r
b) (p$\vee$q$\vee$r)$\wedge$s
c) (p$\wedge$T)$\vee$(q$\wedge$F)