What is the value of (x+3) folders at .10 each

Write a corresponding real world problem to represent 2x - 125=400

Tom wants to order tickets online so that he and three of his friends can go to a water park the cost of the tickets is 16.00 per person there is also a 2.50 one-time service fee for ordering tickets online write an expression in term of n that represents the cost for n ordering tickets online

The square root of 9x plus 7 plus the square rot of 2x equall to 7