Boolean Logic Using Proofs
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ABC' + C = AB + C

I understand this using venn diagrams and intuition. However, I am not able to derive the proof for getting from one side to the other. It's probably very simple step that I keep missing. Please enlighten me.

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2 Answers

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$$AB \overline C + C$$ Identity Law: $X • 1 = X$ $$AB \overline C + 1 • C$$ Annulment Law: $X + 1 = 1$ $$AB \overline C + (AB + 1) C$$ Distributive Law: $X • (Y + Z) = X Y + X Z$ $$AB \overline C + ABC + C$$ Distributive Law: X Y + X Z = $X • (Y + Z)$ $$AB (\overline C + C) + C$$ Complement Law: $X + \overline X = 1$ $$AB + C$$ $$AB \overline C + C = AB + C$$

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Either $C$ is true or false.

If $C$ is true:

$ABC' + C = C$ (or with true is always true)

$AB + C = C$ (or with true is always true)

So $C \implies ABC' + C = AB + C$

If $C$ is false

$ABC' + C$ = ($AB$ and true ) or false = $AB$ or false = $AB$

$AB + C = AB$ or false $= AB$

So $C' \implies ABC' + C = AB + C $

As either one of $C$ or $C'$ is true, $ ABC' + C = AB + C$

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David Miller

David Miller

Executive Financial & Market Analyst

David Miller brings 15 years of experience in global economics, personal finance strategy, and market dynamics. He specializes in turning complex economic trends into actionable insights for everyday readers.

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