Question 87330
Ted paid {{{40/n}}} dollars for each roll
One dollar more than what he paid is {{{40/n + 1}}} dollars
If he sold all but 2 rolls, then he sold {{{n - 2}}} rolls
The amount of money he got from selling the {{{n - 2}}} rolls
is {{{(40/n + 1)(n - 2)}}}
multiplying this out,
{{{40 + n - 80/n - 2}}}
{{{n + 38 - 80/n}}}
multiply the first 2 terms by {{{n/n}}} which is 1
{{{n^2/n + 38n/n - 80/n}}}
Now factor
{{{(1/n)(n^2 + 38n - 80)}}} answer