Answer:
![n(A)=8](https://img.qammunity.org/2020/formulas/mathematics/middle-school/e6lypy7r8g80u96azjgz85pq6mnm1uul4j.png)
![n(B)=5](https://img.qammunity.org/2020/formulas/mathematics/middle-school/jyedzgb74sw153x36v9pa5vhlbucr6lsty.png)
Explanation:
The cardinality is the number of elements in the set.
We need to list the element of the first set A, the set of integers greater than or equal to -8 and less than or equal to - 1
A={-8,-7,-6,-5,-4,-3,-2,-1}
The number of elements in this set is 8.
![\therefore n(A)=8](https://img.qammunity.org/2020/formulas/mathematics/middle-school/qktsf38jaqub71pr1f0lybdwmzy7l77izk.png)
The second set is B={-21, 20, 21, 25, 29}.
The number of elements in this set is 5
![\therefore n(B)=5](https://img.qammunity.org/2020/formulas/mathematics/middle-school/4xq8fv8gupho27mp7ndzwg9xrf0i8onpz9.png)