p → (q ∨ p)

The rule for a ∨ b "It is F only when a is F and b is F, otherwise it's T".
The rule for a → b "It is F only when a is T and b is F, otherwise it's T". 


p | q | q ∨ p | p → (q ∨ p) |
T | T |   T   |   T          |
T | F |   T   |   T          |
F | T |   T   |   T          |
F | F |   F   |   T          |

So p → (q ∨ p) is a tautology because the truth table contains only T's.

Edwin