# Symbolic logic and rules of implication questions [closed]

Question one:

1. (C>D) + (D>B)
2. (B>D) + (E>C)
3. (D>C)
4. B v E /D v B
5. ?
6. ?
7. ?
8. ?
9. D v B

For this question I think the answer involves a constructive dilemma, but for the life of me I cannot arrive to a solvable step. The few sets I could answer are as follows:

1. D v C 2,4, Constructive dilemma
2. C>D 1, Simplification
3. B>D 2, Simplification
4. (?>D) + (?>B) ?,?,?
5. D v B ?,8, Constructive dilemma

Question two:

1. (~K+~N)>[(~P>K)+(~R>G)]
2. K>N
3. ~N+B
4. ~P v ~R /~R v G
5. ?
6. ?
7. ?
8. ?
9. ?
10. ?
11. ?
12. ?

For this problem I got a lot farther in, but I still don't understand how to arrive to a solvable step.

1. ~N 3, Simplified
2. ~K 2,5, Modus tollens
3. ~k+~N 5,6 Conjunction
4. (~P>K)+(~R>G) 1,7 Modus ponens
5. K v G 4,8 Constructive dilemma
6. ~P>K 8, Simplified
7. ?
8. ~RvG ?,?,?

Literally any type of help or hints on either problem would make my weekend. I'm at my wits' end trying to solve these two.

## closed as unclear what you're asking by José Carlos Santos, Shailesh, Mauro ALLEGRANZA, mrtaurho, abc...Feb 10 at 11:11

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• What does it mean "+" in the context of logic ? – Mauro ALLEGRANZA Feb 10 at 10:42
• Too long, too many questions... The first one is unnecessary complicated. – Mauro ALLEGRANZA Feb 10 at 11:04
• "+" should be "or"? – YuiTo Cheng Feb 10 at 11:57
• I provided an answer to a similar question on Philosophy SE: philosophy.stackexchange.com/a/60227/29944 – Frank Hubeny Feb 11 at 12:40