Question

What is the range of the function below:
Let f(x)=9x-1

Answer 1

It's linear function, so its range is
`\mathbb{R}`

Answer 2

The range is -∞ to ∞. (or, All real numbers)
If you keep inputting bigger and bigger numbers, the range gets bigger and bigger. The same kind of thing happens in the negative direction.
And the function is continuous (no holes) so every real number is included.