So this question is worded funny, and I don't really get it but here's what it says.

Prove or disprove the following argument using a truth table, state how the truth table proves or disproves the argument (easy enough)

but then here's what the argument is and how it's formatted:

$a ightarrow (b \vee c)$

$b$

$\therefore eg a \vee eg c$

I get it's Latex and it's really:

a->(b or c)

b

therefore not a or not c

but I don't get how it's formatted and what a truth table looks like for therefore.

Thanks!