There are two ways to work this out: normal variables or using "imaginary" numbers.
Normal variables:
![(7+2i)(3-i)\\(7*3)+[7*(-i)]+(3*2i)+[2i*(-i)]\\21-7i+6i-2i^{2}\\\\21-i-2i^{2}](https://tex.z-dn.net/?f=%20%287%2B2i%29%283-i%29%5C%5C%287%2A3%29%2B%5B7%2A%28-i%29%5D%2B%283%2A2i%29%2B%5B2i%2A%28-i%29%5D%5C%5C21-7i%2B6i-2i%5E%7B2%7D%5C%5C%5C%5C21-i-2i%5E%7B2%7D)
Imaginary numbers:
Using the result from earlier:

Now since

, then the expression becomes:
32.96, to get this answer, you have the divide 890 by 27
The answer should be 101.
Mrs Carson gives the better deal, this is becuase when i set up an inequality 48/6 and 67.50/9, i divided 48 by 2 then added 24 to 48 so i could get them both so i can see what they give, so Mrs Carson gives 72 dollars every 9 hours and thats better than 67.50.
Answer:
145 . this is because angles on a straight line add up to 180 degrees