In 1990, the population of south carolina was approximately 3,500,000. during the

Step-by-step explanation:

Maybe the big numbers make it confusing, so let's look at something simpler.  If you start with 5 marbles and every day you add one marble to it how many will you have x days after startign the collection?  Well on day 0 it's 5, on day 1 it's 6, because 5+1, on day 2 it's 5+2=7, and so on.  You can write this as an equation, y = 5+x, where y is the new total and x is the number of days.  

So let's move that thinking to this problem.  1990 is day 0 and you start with 3,500,000.  Each year now instead of day you add 38,500.  So year 0 has 3,500,000.  year 1 has 3,500,000+38,500 = 3,538,500 and so on, where each year we add another 38,500.  So just like in the simpler example we can rewrite this.  y = 3,500,000 + 38,500x.  Linear means that the x is just an x instead of something like x^2, or 1/x or something else.  Just normal x.  

add 7 to each side

Step-by-step explanation: