Please please help with question 18

Find and simplify an expression for the area of five rows of x squares with side lengths of x centimeters .

Write the system of equations represented by the matrix. 0 1 2 4 -2 3 6 9 1 0 1 3

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?