SOLUTION: What is the truth table for this? Is this valid or invalid? Thank you for your help! S→M, R→M, R ├ S

Algebra ->  Proofs -> SOLUTION: What is the truth table for this? Is this valid or invalid? Thank you for your help! S→M, R→M, R ├ S      Log On


   

Question 980134: What is the truth table for this? Is this valid or invalid? Thank you for your help!
S→M, R→M, R ├ S
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
The premises are the columns marked in blue. The conclusion is the last column.



Notice how the second row has

premise R being true (T)
premise S -> M being true (T)
premise R -> M being true (T)
conclusion S being false (F)

This second row has all premises true with a false conclusion. So this means that the argument is invalid