DOMAIN: Find the domain of the function. In the space provided, type the answer without any spaces between the letters, numbers, or symbols.

Question

f(x) = x² + 8x − 1

Answer 1

The domain means what possible x values could you choose to plug in for x. So, can you choose x = 0? Yes, (0)² + 8(0) - 1 = -1 so that's OK. How about 1 or -1? Yes, those work as well. Lots of times, it's easier to think, "Are there any values that I cannot plug in for x?" I can't think of ANY values that wouldn't be OK to select for x. So the Domain is "all Real Numbers" or, another way to say that is -∞ < x < ∞