Question

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

Answer 1

(-6,0) and (-5,0) I got it right

Answer 2

Answer: It must be between two ordered pair i.e. (-4,0) and (-3,0).

Explanation:

Since we have given that

Quadratic equation :
`x^2+x-9`

First we use the quadratic formula to get the value of x:

`x=(-b\pm√(b^2-4ac))/(2a)\\\\x=(-1\pm√(1+36))/(2* 1)\\\\x=(-1\pm√(37))/(2)\\\\x=(-1+√(37))/(2)\ or\ (-1-√(37))/(2)\\\\x=2.54\ or\ -3.5`

Since the negative root of x is -3.5.

So, it must be between two ordered pair as follows :

(-4,0) and (-3,0).