QuestionApril 19, 2025

What is the y-value of the vertex of the function f(x)=-(x-3)(x+11) -8 -4 33 49

What is the y-value of the vertex of the function f(x)=-(x-3)(x+11) -8 -4 33 49
What is the y-value of the vertex of the function f(x)=-(x-3)(x+11)
-8
-4
33
49

Solution
4.7(91 votes)

Answer

-15 Explanation 1. Expand the function f(x) = -(x-3)(x+11) = -(x^2 + 8x - 33) = -x^2 - 8x + 33 2. Find the x-coordinate of the vertex **Formula:** x = -\frac{b}{2a}; Here, a = -1, b = -8. So, x = -\frac{-8}{2 \times -1} = 4. 3. Calculate the y-value of the vertex Substitute x = 4 into f(x): f(4) = -(4)^2 - 8(4) + 33 = -16 - 32 + 33 = -15.

Explanation

1. Expand the function<br /> $f(x) = -(x-3)(x+11) = -(x^2 + 8x - 33) = -x^2 - 8x + 33$<br />2. Find the x-coordinate of the vertex<br /> **Formula:** $x = -\frac{b}{2a}$; Here, $a = -1$, $b = -8$. So, $x = -\frac{-8}{2 \times -1} = 4$.<br />3. Calculate the y-value of the vertex<br /> Substitute $x = 4$ into $f(x)$: $f(4) = -(4)^2 - 8(4) + 33 = -16 - 32 + 33 = -15$.
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