Question

Between which two ordered pairs does the graph of f(x) = x2 + x – 9 cross the negative x-axis?

Quadratic formula: x =

(–6, 0) and (–5, 0)
(–4, 0) and (–3, 0)
(–3, 0) and (–2, 0)
(–2, 0) and (–1, 0)

Answer 1

we have that

`f(x) =x^(2) + x - 9`

Using a graph tool

see the attached figure

The function represent a vertical parabola that open up

the vertex is a minimum-------> is the point
`(-0.5,-9.3)`

The x-intercepts are the points when the y coordinate is equal to zero

The x-intercepts are the points
`(-3.5,0)` and
`(2.5,0)`

so

the function cross the negative x-axis at point
`(-3.5,0)`

therefore

the answer is

(–4, 0) and (–3, 0)

Answer 2

(-6,0) and (-5,0) is the correct answer