I'm confused on how to simplify variable
for example,
7x-x
and
-3p+6p
?

Basically, simplifying variables is the same as regular equations (like 5-3=2 and 5x-3x=2x)

So 7x-x is the same as 7x-1x which equals 6x

And -3p+6p is the same thing as -3+6 but with a p. With this in mind, the answer is 3p

Hope this helps

$22. if larry's profit were to minimize by one for every hour his store were to be closed, we would subtract 30 by 8.