QUESTION 1 What is the justification for line 5?

1. M v (D & L)

2.B --> ~(MvL) /~B

3. ( M v D ) & ( M v L )

4. ( M v L ) & ( M v D )

5. M v L
6. ~ ~ ( M v L )
7. ~ B

QUESTION 2

Which rule justifies this step:

1. S v (T & R) /S v T

2. (S v T) & (S v R) 1,

QUESTION 3

Which rule justifies this step:

1. S v (T & Q)

2. (T & Q) v S 1,

QUESTION 4

What rule justifies this step?

1. S --> (P --> Q)

2. ~Q /~S (S & P)

3. (S & P) --> Q 1,-

QUESTION 5

What is the justification for line 4?

1. M v (D & L)

2.B --> ~(MvL) /~B

3. ( M v D ) & ( M v L )

4. ( M v L ) & ( M v D )

5. M v L
6. ~ ~ ( M v L )
7. ~ B

QUESTION 6

Which rule justifies this step:

1. P --> (R --> T)

2. (P & R) --> T 1,

QUESTION 7

Complete the proof.

1.P --> (Q & R)

2. ~Q & S /~P

QUESTION 8

Which rule justifies this step:

1. ~~(TvS)

2. T v S 1,

QUESTION 9

Complete the proof.

1. (S v I) --> ~E

2. (E & S) v (E & C) /C

QUESTION 10

Complete the proof.

1. ( P v Q ) --> ~ R

2. S & R /~P