Answer:
Incomplete question
This is the complete aspect of the question
a. Is this true or false
A⊆B?
b. Is this true or false
B⊆A?
Step-by-step explanation:
Given that
A = {n ℤ | n = 5r for some integer r}
Integer are positive and negative whole numbers
A={...-20,-15,-10,-5,0,5,10,15,20...}
Also,
B ={mℤ |m = 20s for some integer s}.
Then,
B={....-80,-40,-20,0,20,40,80....}
a. In mathematics, a set A is contained in B if every element in A is found in B
Then,
A⊆B
Then looking at A and B, not all element in A can be found in B e.g, 10, 15,25,-10,-25 and so, the law doesn't hold
Then, A⊆B is false
b. B⊆A, now every element in B can be found in A, then this is true and then B is contain in A
