How do you put this equation in vertex form?

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?

Rewrite the following quadratic functions in intercept or factored form. show your work. y = 5x^2 + 10x

Collin did the work to see if 10 is a solution to the equation r/4=2.4