I need help with exponents

Fiona joins a fruit of the month club. the entry cost was $25 and then she pays $18 per month. if she participates for 8 months, how much will she pay in all? how much in 10 months?

The base of a triangle exceeds the height by 7 centimeters. if the area is 400 square centimeters, find the length of the base and the height of the triangle.

Ateacher noticed 5/8 of the students were wearing either blue shorts or white shorts. write two different ways this could be done.