Graphing art #1 parallel lines, what is the equation of the lines and all the lines in the graph

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?

Solve -2(4y + 6) = 52. 5 -5 8 -8 and !

Asap! i'm not good math and i'm lost.