Suppose n(u) = w, n(a) = x, n(b) = y, and n(a ∪ b) = z. (a) why must x be less than or equal to z? a ⊆ (a ∪ b) (a ∪ b) ⊆ a        (a ∪ b) ⊆ b a ⊆ (a ∩ b) (a ∩ b) ⊆ a

First, note some definitions:

1. A set is a collection of distinct objects, considered as an object in its own right.

2. If A is a set, then n(A) is a number of elements in A.

3. Set X is a subset of a set Y if and only if every object of X is also an object of Y. Here use notation X⊆Y.

4. A set X∪Y is called union of sets X and Y. This is the set of all distinct elements that are in X or Y.

Now remember that

Then n(A)≤n(A∪B) (or x≤z), because A ⊆ (A ∪ B).

i think 1: 2

step-by-step explanation:

answer: 10 meter

step-by-step explanation:

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