Simplify by combining like terms : 5а + 25 — 3а 4

One month, a music site observed that 60% of the people who downloaded songs from its site downloaded q sam's latest single. the equation below represents this information, where x represents the total number of people who ddownloaded songs from the site that month: x = 0.6x + 384 how many people who downloaded songs from the site that month downloaded q sam's latest single?

How do you use the elimination method for this question? explain, because i really want to understand!

What is the perimeter of a rectangular building that is 80 feet wide and 140 feet deep?