The answer should be (7x+1)(7x-1)
16= 6 ones or 16 ones
817= 8 hundreds and 7 ones or 17 ones
Hope this helps! :D
By "density" I assume you mean "probability density function". For this to be the case for

, we require

Since

you have

which means
If the top of the fraction is less than the bottom, the fraction is less than one. However, Federico has raised 11/10 of what he needs and the top is bigger than the bottom so he’s raised the most money.