Between which two ordered pairs does the graph of f(x) = one-halfx2 + x – 9 cross the negative x-axis?

Quadratic formula: x = StartFraction negative b plus or minus StartRoot b squared minus 4 a c EndRoot Over 2 a EndFraction

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

Respuesta :

None of Option are correct

Step-by-step explanation:

The Given function is f(x) = y = [tex]\frac{1}{2} x^{2} + x -9[/tex]

Here, f(x) is quadratic function and it asked that when function cross the Negative X-axis.

If any function cross the X-axis then, Point of intersection will have y component as zero.

Therefore, f(x) = y = [tex]\frac{1}{2} x^{2} + x -9 [/tex]

y = [tex]\frac{1}{2} x^{2} + x -9 = 0 [/tex]

Solving quadratric equation,

Comparing with [tex] ax^{2} + bx + c= 0 [/tex]

We get a=[tex]\frac{1}{2}[/tex], b=1, c=(-9)

Since,

[tex]x=\frac{-b+\sqrt{b^{2}-4ac }  }{2a}[/tex]

[tex]x=\frac{- 1+\sqrt{(1)^{2}-4(\frac{1}{2})(-9) }}{2(\frac{1}{2})}[/tex]

[tex]x=\frac{-1+\sqrt{1+(2)(9)}}{1}[/tex]

[tex]x=\frac{-1+\sqrt{19}}{1}[/tex]

[tex]x=-1+\sqrt{19}and x=-1-\sqrt{19}[/tex]

Thus, None of option are correct.

Verification.....

A) (–6, 0) and (–5, 0) give quadratic function : y = [tex]x^{2} + 11x +30 [/tex]

B) (–4, 0) and (–3, 0) give quadratic function : y = [tex]x^{2} + 7x +12 [/tex]

C) (–3, 0) and (–2, 0) give quadraric function : y = [tex]x^{2} + 5x +6 [/tex]

D) (–2, 0) and (–1, 0) give quadratic function : y = [tex]x^{2} + 3x +2 [/tex]

Answer:

its a (-6,0) and (-5,0)

Step-by-step explanation: