Question

The cost in dollars to print n books is 500 + 10n.
How many books are printed for a cost of $15 000?

Answer 1

500 + 10n = 15,000

Subtract 500 from each side:

10n = 14,500

Divide each side by 10 :

n = 1,450 books

Answer 2

$500+10n=15.000 \\ \\ 500-500+10n =15.000-500 \\ \\ 10n=14.500 \\ \\ n= \frac{14.500}{10} \\ \\ \boxed{n=1.450}$