Answer:

Step-by-step explanation:
We need to find 
We know that √-1 = i
Adding -49 and -4 and solving

Since 53 is not a perfect square so our answer is:

C= 20-0.75x
c= 20-0.75(9)
c= 20-6.75
c= 13.25
Here c is the amount of change and x is the number of books bought.
The customer's change will be $13.25
Alright! So to solve these questions, you need to find out the difference. You can use ratios to solve this. For example, question #25:
A class had 30 pupils at the beginning of this school term, but now has 5 more pupils. What is the percent of increase?
The question is basically asking how much 5 is in ratio to 30. So just divide 5 (the given amount) by 30 (the total amount). The answer is 0.16, or 16%