Question

Jordan is kayaking upstream. The following equation models his speed: f(x) = 2x2 − 4x − 9, where x is Anna's speed relative to land. What is the domain of the function? x ≥ 1 x ≤ −4 x ≥ −9 All real numbers

Answer 1

All real numbers

Explanation:

The domain of a continuous parabola is always all real numbers or −∞ ≤ x ≤ ∞ because the ends of the parabola continue forever and when you graph this equation, you see that the ends of the parabola never stops, it continues on and on and on.

Answer 2

All real numbers

Explanation:

The given equation is:

`f(x) = 2 {x}^(2) - 4x - 9`

where x is Ana's speed.

This is a quadratic function.

A quadratic function is a polynomial function.

All polynomial functions are are continuous and defined for all real values of x.

Therefore the domain of

`f(x) = 2 {x}^(2) - 4x - 9`

is all real numbers.