Identify the vertex of y=-1(x-4)^2+9 and tell whether it’s a minimum or maximum

Answer:
B. (4,9), maximum
Step-by-step explanation:
The given function is
[tex]y=-1(x-4)^2+9[/tex]
This function is of the form;
[tex]y=a(x-h)^2+k[/tex]
where (h,k)=(4,9) is the vertex.
and [tex]a=-1[/tex] since 'a' is negative the vertex is the maximum point on the graph of this function.
The correct answer is B
Answer: option B
Step-by-step explanation:
Given the quadratic equation [tex]y=-1(x-4)^2+9[/tex], you can use the formula to find the x-coordinate of the vertex of the parabola:
[tex]x=\frac{-b}{2a}[/tex]
Simplify the quadratic equation. Remember that:
[tex](a-b)^2=a^2-2ab+b^2[/tex]
Then:
[tex]y=-1(x-4)^2+9\\y=-1(x^2-2(x)(4)+4^2)+9\\y=-x^2+8x-16+9\\y=-x^2+8x-7[/tex]
Substituting:
[tex]x=\frac{-8}{2(-1)}=4[/tex]
The y-coordinate is:
[tex]y=-(4)^2+8(4)-7=9[/tex]
The vertex is at (4,9) therefore it is a maximum.