Using the completing-the-square method, find the vertex of the function f(x) = –3x2 + 6x − 2 and indicate whether it is a minimum or a maximum and at what point.

A. Maximum at (1, 1)
B. Minimum at (1, 1)
C. Maximum at (–1, 2)
D. Minimum at (–1, 2)


Respuesta :

we have

[tex]f(x) =-3x^{2}+ 6x-2[/tex]

Since the leading coefficient is negative, the function has a maximum

Let

y=f(x)

[tex]y=-3x^{2}+ 6x-2[/tex]

Group terms that contain the same variable, and move the constant to the opposite side of the equation

[tex]y+2=-3x^{2}+ 6x[/tex]

Factor the leading coefficient

[tex]y+2=-3(x^{2}-2x)[/tex]

Complete the square. Remember to balance the equation by adding the same constants to each side

[tex]y+2-3=-3(x^{2}-2x+1)[/tex]

[tex]y-1=-3(x^{2}-2x+1)[/tex]

Rewrite as perfect squares

[tex]y-1=-3(x-1)^{2}[/tex]

[tex]y=-3(x-1)^{2}+1[/tex]

the vertex is the point [tex](1,1)[/tex]

therefore

the answer is the option

A. Maximum at (1, 1)