Question

Between which two ordered pairs does the graph of f(x) = 1/2x2 + x – 9 cross the negative x-axis? (–6, 0) and (–5, 0) (–4, 0) and (–3, 0) (–3, 0) and (–2, 0) (–2, 0) and (–1, 0)

Answer 1

Between (-6,0) and (-5,0).

Explanation:

When it crosses the x axis, it's an x-intercept. To find the x-intercept, set y (aka f(x)) to zero. The solutions to the equation are approximately 3.36 and - 5.36. Since you're finding the negative x-intercept, you only need the negative solution - 5.36. This is in between (-6,0) and (-5,0).