What expression is equivalent to 3 7+x

You have 3 boxes, one "strawberries"; one "mentos" and one "mixed".but you know that all the labels are in incorrect order .how do you know witch is witch?

Which of the following points is a solution to the system of equations shown? y - x = -1 x + y = -5

Jessie sorted the coins in her bank she made 7 stacks or 6 dimes and 8 stacks of 5 nickels she then found 1 dime and 1 nickel how many dimes and nickels dose jessie have in all?