Answer:
[tex]f(x) = (x-1)^{2} -7[/tex] is the correct answer.
Step-by-step explanation:
Given that function f(x) is:
[tex]f(x) = x^{2} -2x-6[/tex]
f(x) is a quadratic function in x, meaning that it has a maximum power of 2 of x.
Vertex form of quadratic function is given as:
[tex]f (x) = a(x - h)^2 + k[/tex]
i.e. we make whole square of terms of [tex]x[/tex].
Now, let us try to make whole square term of [tex]x[/tex].
[tex]f(x) = x^{2} -2x-6[/tex]
Adding and subtracting 1 from RHS:
[tex]f(x) = x^{2} -2x-6+1-1\\f(x) = (x^{2} -2x+1)-1-6\\f(x) = (x^{2} -2\times x\times 1+1^2)-7[/tex]
Now, using the formula:
[tex](a-b)^2 = a^2 -2ab+b^2[/tex]
The given function becomes:
[tex]f(x) = (x-1)^{2}-7[/tex]
It is comparable to vertex form i.e. [tex]f (x) = a(x - h)^2 + k[/tex]
where a = 1, h = 1 and k = -7
Hence, the vertex form of given function is:
[tex]f(x) = (x-1)^{2}-7[/tex]