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Which statement about the graph of the function f(x)=2x^2-x-6 are true?

A. The domain of the function is {x|x > (1/4)}
B. The range of the function is all real number
C. The vertex of the function is [(1/4)-6(1/8)]
D. The function has two x-intercepts
E. The function is increasing over the interval (-6(1/8), infinity )

Respuesta :

c the vertex of the function

Answer:

C. The vertex of the function is [(1/4)-6(1/8)]

Step-by-step explanation:

The given function is

[tex]f(x)=2x^{2} -x-6[/tex]

This function is a quadratic function.

Its domain is always all real number.

Its range is determined and restricted by its vertex, that is, it can't be all real numbers.

The vertex has coordinates [tex](h,k)[/tex], where

[tex]h=-\frac{b}{2a}[/tex]

Having [tex]a=2, b=-1, c=-6[/tex]

Replacing these values, we have

[tex]h=-\frac{b}{2a}=-\frac{-1}{2(2)}=\frac{1}{4}[/tex]

Then, [tex]k=f(h)[/tex], that is, we need to replace the value we found

[tex]f(x)=2x^{2} -x-6\\f(\frac{1}{4})=2(\frac{1}{4} )^{2} -\frac{1}{4}-6=\frac{2}{16}- \frac{25}{4}=\frac{2-100}{16}\\ k=\frac{-98}{16} =-6\frac{1}{8}[/tex]

Therefore, the right answer is C. The vertex of the function is [(1/4)-6(1/8)]

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