Why choose to add or sub tract when subtracting an expression

Abox of chocolates costs $7. which equation relates the number of boxes sold (x) and total cost of the boxes sold (y)?

Jenny earned a 77 on her most recent test jenny score is no less then 5 points greater then 4/5 of terrance’s score if t represents terrance score which inequality represents the situation

Harry is at the depot in dover and has deliveries to make in edinburgh, glasgow and aberdeen. from dover which of the deliveries is the shortest distance?