Answer:
12.3
Step-by-step explanation:
subtract(its me again)
We are to show that if X ⊆ Y then (X ∪ Z) ⊆ (Y ∪ Z) for sets X, Y, Z.
Assume that a is a representative element of X, that is, a ∈ X. By the definition of union, a ∈ X ∪ Z. Now because X ⊆ Y and we assumed a ∈ X, then a ∈ Y by the definition of subset. And because a ∈ Y, then a ∈ Y ∪ Z by definition of union.
We chose our representative element, a, and showed that a ∈ X ∪ Y implies that a ∈ Y ∪ Z and this completes the proof.
The total calories burnt in 20 minutes are 200
Step-by-step explanation:
We have to do simple multiplication to find the number of calories burnt.
Given
Number of calories burnt in one minute = c = 10
Time = t = 20 min
So the total number of calories burnt in 20 minutes will be:

Hence,
The total calories burnt in 20 minutes are 200
Keywords: Integers, unit
Learn more about integers at:
#LearnwithBrainly
Answer:
B. AC > AB
Step-by-step explanation:
AC is the longest line and AB is shorter than AC