10. Two workers were hired to begin work at the same time. Worker A's contract called for a starting salary of $20,000 with an increase of $800 after each year of employment. Worker B's contract called for a starting salary of $15,200 with an increase of $2,000 after each year of employment. If x represents the number of full years of employment (that is, the number of yearly increases each worker has received), which of the following equations could be solved to determine the number of years until B's yearly salary equals A's yearly salary?