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).

idk

step-by-step explanation:

see explanation

step-by-step explanation:

since the sequence is geometric there is a common ratio r between consecutive terms, that is

r = 4 ÷ - 2 = - 2

r = - 8 ÷ 4 = - 2

r = 16 ÷ 8 = - 2

the next term - 13 must be incorrect as it should be - 32 for the sequence to be geometric.

the first 4 terms are therefore geometric with common ratio r = - 2