What is domain and range

What are the coordinates of the midpoint of ab? ,1/2) /2,-1) ,-3/2) /2,-2)

Handsome jack is buying a pony made of diamonds. the price of the pony is p dollars, and jack also has to pay a 25% diamond pony tax. which of the following expressions could represent how much jack pays in total for the pony?

In a sale there is 25% of all prices a chair costs £45 in sale how much was it before the sale