(Timed) Solve the system of equations work shown

Can someone check if i did this right since i really want to make sure it’s correct. if you do you so much

Lola says these two expressions have the same value. expression a expression b which explains whether lola is correct?

Charlie is at an amusement park that has 18 different rides. each ride costs $1.75. the function c(r) = 1.75r represents the total amount of money that charlie will spend if he goes on r rides, but he never goes on the same one more than once. what domain and range are reasonable for the function?