6.B. Page 138
L-true: 2, 5, 21, 22, 23.
L-false: 10, 12, 14, 16, 26, 28.
L-indeterminate: 1, 3, 4, 6, 7, 8, 9, 11, 13, 15, 17, 18, 20, 24, 25, 27, 29. 30.
6.C. Pages 138-141 (Note: '&' is used for the dot; '//' separates premises; '|-' is the conclusion indicator)
1. (A <-> R) // R |- (A -> C) (Invalid)
2. (P -> L) // (L -> S) |- (S v -P) (Valid)
3. (T -> -R) // (D -> -A) // (-D -> P) |- (R -> -A) (Invalid)
4. (S v H) // (-G -> -S) |- (H -> G) (Invalid)
5. See the book, page 234.
6. [(J & E) -> -C] // (E -> C) // -E |- (-E & -J) (Invalid)
7. (G v U) // [(M -> G) & (-M -> U)] // -M |- -G (Invalid)
8. (B -> R) // [-(R & M) -> B] |- R (Valid)
9. (R -> G) // (A -> I) // [M -> (R v A)] // M |- (G v -I) (Invalid)
10. See the book, page 234.
11. [(L & G) -> (-P v W)] // [(P v I) -> L] // [(P v E) -> G] // (P & J) |- W (Valid)
12. (L -> P) // (R -> L) // (B -> -L) // (P -> D) |- -L (Invalid)
13. (F -> T) // (T -> P) // -P // (W -> F) // (W v F) |- (P v P) (Valid)
14. (R -> A) // [(H & W) -> R] // (A -> B) // -B // |- (-H v –W) (Valid)
15. See the book, page 234.
16. (A -> G) // (G -> U) // (A v G) |- [(A v U) & (A -> U)] (Valid)
17. There are two arguments here. Argument #1 is presented in the first sentence, where 'since' is the premise indicator. First arg: T |- (P -> D) (Invalid)
17. Second arg: (P -> D) // [(R v C) -P] // (C & -S) |- D (Valid) [Note here that I used the conclusion of the first arg as the first premise of the second arg.]
18. [(C & P) v (C & S)] // [(C v N) -> L] |- L (Valid)
19. [(S -> F) v (M & W)] // -(M & W) // -F |- -S (Valid)
20. See the book, page 234.