Triangle DEF has vertices D (-6,3), E (--1,5), F (7,3). Find the area of triangle DEF

Ill mark the brainliest if you me with the these three questions 7,8,9

Joe has a rectangular chicken coop. the length of the coop is 4 feet less than twice the width. the area of the chicken coop is 510 square feet. what is the length of the chicken coup?

Acd that is originally priced at $15.85 red-tagged for the sale. what is the sale price of the cd