Answer:
Domain: all real numbers. Range: (-∞, 2000]
Explanation:
f(x)=2.5x is a simple "ramp" function, a linear function and a polynomial. As such, its domain contains "all real numbers." That value 800 defines the largest value that this f(x) can have: f(800) = 2.5(800) = 2000.
Thus, the range is "all real numbers from -∞ through and including 2000."