Find the absolute value of -13

Which two undefined geometric terms always describe figures with no beginning or end?

Ineed the solution to this problem and the steps.

Pranav and molly are selling pies for a school fundraiser. customers can buy blueberry pies and pumpkin pies. pranav sold 6 blueberry pies and 4 pumpkin pies for a total of $106. molly sold 6 blueberry pies and 3 pumpkin pies for a total of $90. find the cost of each of one blueberry pie and one pumpkin pie