This is a distributive minus sign problem and the Regents has anticipated negative sign mistakes so be careful!!

R(x) = -0.5x^2 + 800x – 100
C(x) = 300x + 250
so R(x) – C(x) is
-0.5x^2 + 800x – 100 – (300x + 250)
-0.5x^2 + 800x – 100 – 300x – 250
combine like terms and watch your signs

2 more points!!!!!