16 thru 23 look wrong and 16 is absolutely wrong. You use this:https://www.mathpapa.com/algebra-calculator.html to work out the answers and it shows the steps and explains it to you better than I could. Good luck
The cube root of 81 is 4.32674871092
Transaction 3 - $143
transaction 4 - $-86
transaction 5 - $86
The answer is m = -59/42
Step by step explanation is in the image below.