$1\mathrm{.}12\mathrm{.}4$: Proving arguments in English are valid using rules of inference.

Prove that each argument is valid by replacing each proposition with a variable to obtain the form of the argument. Then use the rules of inference to prove that the form is valid.

$($a$)$

If I drive on the freeway, I will see the fire.

I will drive on the freeway or take surface streets $($or both$).$

I am not going to take surface streets.

I will see the fire.