Im not exactly understanding this question. Can someone please help me and possibly explain this to me?

Yesterday i ran 5 miles. today, i ran 3.7 miles. did my percent increase, decrease or is it a percent error? plz i need

Felix wrote several equations and determined that only one of the equations has no solution. which of these equations has no solution?

Write a function rule for  “the output is  5 less than the input.” let  x be the input and let  y  be the output.