Thread: prove by rules of inference

I have premises
(1)
(2)
(3)
and conclusion
( ) r

I've checked that the argument is valid.
But I still cannot find a way to show it by using rules of inference.
please...

Which exactly system of inference rules are you using? See this sticky thread.

something like this.
List of rules of inference - Wikipedia, the free encyclopedia

Originally Posted by deniselim17

I have premises
(1)
(2)
(3)
and conclusion
( )

From (3) we get by addition.

Then by material implication we get .

Another way is to have just because r is a premise and use the Deduction theorem (or Conditional Introduction).

So, premise (1) and premise (2) are not really necessary here?

That's right.