Which of the following is not an attribute of a linear equation? The equation is of the first degree. The equation has a single variable. The variable must be raised to the second power. The equation has an equal sign.

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?