The answer for this problem would be 7x+6
Let's solve this problem step-by-step.
4x−3+3x+9
=4x+−3+3x+9
Step 1: Combine Like Terms.
=4x+−3+3x+9
=(4x+3x)+(−3+9)
So, the answer for this problem would be 7x+6.
If we rearrange the given data set from lowest to highest, we have

The minimum is 3.
The first quartile is the average of 6 and 7, which is 6.5
The median is the average of 8 and 10 which is 9.
The third quartile is the average of 12 and 15 which is 13.5.
The maximum is 18.
70 * 0.22 = 15.4
70 + 15.4 = $85.40
The total cost is $85.40