I've partially completed it but I have no idea how to prove CD/CE is equal to GD/FE

Cassie is traveling 675 miles today to visit her brother and his family. so far, she has stopped for gas three times. at the first stop, she put in 7.1 gallons of gas and paid $23.79. at her second stop, she put in 5.8 gallons of gas and paid $19.08. and, at the third stop, 6.6 gallons and paid $20.39. at which stop did casey pay the most for gas?

Hello can you me find all the products

What are the solutions of the system? solve by graphing. y = -x^2 - 3x + 2 y = -2x + 2