Hi i need some : ) -10/3 times -2/1

How do you use the elimination method for this question? explain, because i really want to understand!

Aclothing store has the sign shown in the shop window. pani sees the sign and wants to buy 3 shirts and 2 pairs of jeans. the cost of each shirt before the discount is $12, and the cost of each pair of jeans is $19 before the discount. write and simplify an expression to find the amount pani pays if a $3 discount is applied to her total

Use circumcenter theorem to solve for the given values