pls help immediately! only answer if you know how to do this! giving extra points bc i really need this !

Can someone me and plz do the problem

Given that abcd is a rhombus, what is the value of x?

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?