Question

Which function has a vertex at (2, –9)? f(x) = –(x – 3)2 f(x) = (x + 8)2 f(x) = (x – 5)(x + 1) f(x) = –(x – 1)(x – 5

Answer 1

Answer:

c

Step-by-step explanation:

Answer 2

The function that has a vertex at (2, -9) is;

C: f(x) = (x - 5)(x + 1)

How to find the vertex of a Function?

The formula for x-coordinate of a vertex is;

x = -b/2a

The correct function is Option C with f(x) = (x - 5)(x + 1).

We will expand to get;

f(x) = x² -5x + x - 5

f(x) = x² - 4x - 5

Putting 2 for x gives;

f(2) = 2² - 4(2) - 5

f(2) = -9

Also, x = -b/2a = -(-4)/(2*1) = 2

Thus, it is proved that option C has it's vertex at 2, -9

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