I really need help with how I get the solution I can’t tell whether it’s no solution or infinite or none please help due today thank you.

Can someone answer these problems for me

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?

In which form is the following function written? y = - 2(x – 3)(x + 5)