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## Homework Statement

I am trying to prove the absorption law

A U (A ∩ B) = A

I know that a way to prove this is to show that each is a subset of the other but I'm a little confused about one part in the process (below)

## Homework Equations

## The Attempt at a Solution

Let x∈A U (A ∩ B)

then x∈A or x∈(A ∩ B)

so because x∈A then we know that A U (A ∩ B) ⊆ A (I don't understand why this line is true.)

Why just because x∈A does it mean that A U (A ∩ B) ⊆ A is true? Any help is greatly appreciated.