Question 1167022
−0.5(x−110)^2+6,050-(30x+250) is the profit function
This is -0.5(x^2-220x+12100)+6050-30x-250
or -0.5x^2+110x-6050+6050-30x-250
or -0.5x^2+80x-250
{{{graph(300,300,-40,200,-500,3000,-0.5x^2+80x-250)}}}
The domain is all x but -units make no sense and 1000 units is a large loss.
At 80 units the profit is -3200+6400-250 or $2950
at 90 units it is $2800
The maximum is when x=-b/2a or -80/-1 or 80 units.

With squared functions as production (in this instance) increases, there could be decreasing revenue simply because the company may oversupply and have to either store or sell at a lower price.  This is an economics question rather than a math question.