Question

Which of the following functions best describes this graph?​

Answer 1

D. y = x^2 - 9x + 20

Explanation:

According to the graph, y = 0, when x = 4 and when x = 5.

Therefore, we must calculate the roots of each answer.

A. y = (x + 4) (x + 5)

0 = (x + 4) (x + 5)

(x + 4) = 0 => x = -4

(x + 5) = 0 => x = -5

B. y = (x - 3) (x + 4)

0 = (x - 3) (x + 4)

(x - 3) = 0 => x = 3

(x + 4) = 0 => x = -4

C. y = x^2 - 8x +18

In this case, when we apply the general equation, we are left with

`x = 4 + √(2)i`

`x = 4 - √(2)i`

D. y = x^2 - 9x + 20

0 = (x - 4)(x - 5)

(x - 4) = 0 => x = 4

(x - 5) = 0 => x = 5

Therefore the answer is D. y = x^2 - 9x + 20