Help me find area guys please

Ineed in figuring out this problem.

Sophia wrote an equation to represent the revenue of a movie theater for one day. she let x represent the number of child tickets sold and y represents the nunver of adult tickets sold. if a child ticket cost $4, an adult ticket cost $6, and the total revenue for the daybwas $420, which equation could sophia use to represent the number of chikd and adult tickets that were sold?

Jubal wrote the four equations below. he examined them, without solving them, to determine which equation has no solution. which of jubal’s equations has no solution hurry