Consider the following in Boolean Algebra \(\begin{array}{l} \mathrm{X}: a…

2022

Consider the following in Boolean Algebra

\(\begin{array}{l} \mathrm{X}: a \vee(b \wedge(a \vee c))=(a \vee b) \wedge(a \vee c) \\ \mathrm{Y}: a \wedge(b \vee(a \wedge c))=(a \wedge b) \vee(a \wedge c) \\ a \vee(b \wedge c)=(a \vee b) \wedge c \text { is satisfied if } \\ \end{array}\)

  1. A.

    X is true

  2. B.

    Y is true

  3. C.

    Both X and Y are true

  4. D.

    It does not depend on X and Y

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Correct answer: C

Answer: Both X and Y are true. Below are concise derivations for each identity.

  • X: Start with a ∨ (b ∧ (a ∨ c)).

    Apply distributivity inside: b ∧ (a ∨ c) = (a ∧ b) ∨ (b ∧ c).

    Then a ∨ ((a ∧ b) ∨ (b ∧ c)) = a ∨ (b ∧ c), using absorption a ∨ (a ∧ b) = a.

    Also (a ∨ b) ∧ (a ∨ c) = a ∨ (b ∧ c) by distributivity. Hence the two sides are equal for all a, b, c.

  • Y: Start with a ∧ (b ∨ (a ∧ c)).

    Apply distributivity inside: b ∨ (a ∧ c) = (b ∨ a) ∧ (b ∨ c) = (a ∨ b) ∧ (b ∨ c).

    Then a ∧ ((a ∨ b) ∧ (b ∨ c)) = a ∧ (b ∨ c), using absorption a ∧ (a ∨ b) = a.

    Also (a ∧ b) ∨ (a ∧ c) = a ∧ (b ∨ c) by distributivity. Hence both sides are equal for all a, b, c.

Therefore both identities hold universally; the correct choice is that both X and Y are true.

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