The graph shows [tex]$g(x)=x^2-9x+20$[/tex].

What are the x-intercepts of [tex]$g(x)$[/tex]?

A. (4.5, 0) and (5, 0)

B. (0, 4.5) and (0, 5)

C. (0, 5) and (0, 4)

D. (5, 0) and (4, 0)



Answer :

To determine the x-intercepts of the quadratic function [tex]\( g(x) = x^2 - 9x + 20 \)[/tex], we need to find the values of [tex]\( x \)[/tex] for which [tex]\( g(x) = 0 \)[/tex].

The function [tex]\( g(x) = x^2 - 9x + 20 \)[/tex] can be rephrased as:
[tex]\[ x^2 - 9x + 20 = 0 \][/tex]

This is a quadratic equation in standard form [tex]\( ax^2 + bx + c = 0 \)[/tex]. To find the x-intercepts, we solve this quadratic equation.

We can use the quadratic formula to solve for [tex]\( x \)[/tex]:
[tex]\[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \][/tex]

In this equation:
- [tex]\( a = 1 \)[/tex]
- [tex]\( b = -9 \)[/tex]
- [tex]\( c = 20 \)[/tex]

Substitute these values into the quadratic formula:
[tex]\[ x = \frac{-(-9) \pm \sqrt{(-9)^2 - 4 \cdot 1 \cdot 20}}{2 \cdot 1} \][/tex]
[tex]\[ x = \frac{9 \pm \sqrt{81 - 80}}{2} \][/tex]
[tex]\[ x = \frac{9 \pm \sqrt{1}}{2} \][/tex]
[tex]\[ x = \frac{9 \pm 1}{2} \][/tex]

This gives us two solutions:
[tex]\[ x = \frac{9 + 1}{2} = \frac{10}{2} = 5 \][/tex]
[tex]\[ x = \frac{9 - 1}{2} = \frac{8}{2} = 4 \][/tex]

Thus, the x-intercepts of the quadratic function [tex]\( g(x) = x^2 - 9x + 20 \)[/tex] are [tex]\( x = 5 \)[/tex] and [tex]\( x = 4 \)[/tex].

This corresponds to the intercept points [tex]\((5, 0)\)[/tex] and [tex]\((4, 0)\)[/tex].

Therefore, the correct answer is:
[tex]\[ (5,0) \text{ and } (4,0) \][/tex]

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