Is there supposed to be an x before 4x?
Step-by-step explanation:

Try putting it on a timeline. It makes more sense that way :)
Given:
Salary = $400 a month
Rate of commission = 10%
Total sales = $2000
To find:
The total money you will make this month.
Solution:
We have,
Rate of commission = 10%
Total sales = $2000
Commission = 
= 
We know that,
Total money = Salary + Commission
= 
= 
Therefore, the total money you will make this month is $600.
Answer:
8 games
Step-by-step explanation:
The team has won 13 games so far and needs to win 21.
For this problem, you would solve 21 - 13, which is 8.