4. There are 9x - 7 customers in a store on Monday and 5x + 15 customers on Tuesday. What is the total number of customers for the two days? *

Refer to interactive solution 17.45 to review a method by which this problem can be solved. the fundamental frequencies of two air columns are the same. column a is open at both ends, while column b is open at only one end. the length of column a is 0.504 m. what is the length of column b?

Can someone explain to me how to do

The difference of two numbers is 40. find the numbers if 0.3 parts of one number is equal to 37.5% of the other one.