2. If [tex]$A=\{x: x$ is a positive integer $\ \textless \ 8\}, B=\left\{x: x^3-6 x^2+11 x-6=0\right\}$[/tex] and [tex][tex]$C=\{x: x$[/tex] is even$ \}$[/tex], show that:

a. [tex]$A \cap(B \cup C)=(A \cap B) \cup(A \cap C)$[/tex]



Answer :

Certainly! Let's begin by defining the sets given in the problem and then showing the required set relationship. Here are the sets:

- [tex]\( A \)[/tex]: [tex]\( A = \{ x: x \text{ is a positive integer } < 8 \} \)[/tex]. This means [tex]\( A = \{ 1, 2, 3, 4, 5, 6, 7 \} \)[/tex].
- [tex]\( B \)[/tex]: [tex]\( B = \left\{ x : x^3 - 6x^2 + 11x - 6 = 0 \right\} \)[/tex]. Solving this equation, we find the roots, which are the integers [tex]\( B = \{ 1, 2, 3 \} \)[/tex].
- [tex]\( C \)[/tex]: [tex]\( C = \{ x : x \text{ is even and } x < 8 \} \)[/tex]. Thus, [tex]\( C = \{ 0, 2, 4, 6 \} \)[/tex].

Next, we follow the steps to solve the expression [tex]\( A \cap (B \cup C) = (A \cap B) \cup (A \cap C) \)[/tex].

### Step-by-Step Solution:

1. Find the Union of [tex]\( B \)[/tex] and [tex]\( C \)[/tex]:

[tex]\[ B \cup C = \{ 1, 2, 3 \} \cup \{ 0, 2, 4, 6 \} = \{ 0, 1, 2, 3, 4, 6 \} \][/tex]

2. Find the Intersection of [tex]\( A \)[/tex] with [tex]\( B \cup C \)[/tex]:

[tex]\[ A \cap (B \cup C) = \{ 1, 2, 3, 4, 5, 6, 7 \} \cap \{ 0, 1, 2, 3, 4, 6 \} = \{ 1, 2, 3, 4, 6 \} \][/tex]

3. Find the Intersection of [tex]\( A \)[/tex] with [tex]\( B \)[/tex]:

[tex]\[ A \cap B = \{ 1, 2, 3, 4, 5, 6, 7 \} \cap \{ 1, 2, 3 \} = \{ 1, 2, 3 \} \][/tex]

4. Find the Intersection of [tex]\( A \)[/tex] with [tex]\( C \)[/tex]:

[tex]\[ A \cap C = \{ 1, 2, 3, 4, 5, 6, 7 \} \cap \{ 0, 2, 4, 6 \} = \{ 2, 4, 6 \} \][/tex]

5. Find the Union of [tex]\( A \cap B \)[/tex] and [tex]\( A \cap C \)[/tex]:

[tex]\[ (A \cap B) \cup (A \cap C) = \{ 1, 2, 3 \} \cup \{ 2, 4, 6 \} = \{ 1, 2, 3, 4, 6 \} \][/tex]

### Conclusion:

From the above steps, we find that:
[tex]\[ A \cap (B \cup C) = \{ 1, 2, 3, 4, 6 \} \][/tex]
and
[tex]\[ (A \cap B) \cup (A \cap C) = \{ 1, 2, 3, 4, 6 \} \][/tex]

Since both sides of the equation yield the same set, we have shown that:
[tex]\[ A \cap (B \cup C) = (A \cap B) \cup (A \cap C) \][/tex]

Thus, the equality is proved.

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