The function h(x) = x2 + 14x + 41 represents a parabola.
Part A: Rewrite the function in vertex form by completing the square. Show your work. (6 points)
Part B: Determine the vertex and indicate whether it is a maximum or a minimum on the graph. How do you know? (2 points)
Part C: Determine the axis of symmetry for h(x). (2 points)

Respuesta :

Part A:

[tex]h(x)= x^{2} +14x+41[/tex]

The first step of completing the square is writing the expression [tex] x^{2} +14x[/tex] as [tex] (x+7)^{2} [/tex] which expands to [tex] x^{2} +14x+49[/tex].

We have the first two terms exactly the same with the function we start with: [tex] x^{2} [/tex] and [tex]14x[/tex] but we need to add/subtract from the last term, 49, to obtain 41. 

So the second step is to subtract -8 from the expression [tex] x^{2} +14x+49[/tex]

The function in completing the square form is
[tex]h(x)= (x+7)^{2}-8 [/tex]

Part B:

The vertex is obtained by equating the expression in the bracket from part A to zero

[tex]x+7=0[/tex]
[tex]x=-7[/tex]

It means the curve has a turning point at x = -7

This vertex is a minimum since the function will make a U-shape. 
A quadratic function [tex]a x^{2} +bx+c[/tex] can either make U-shape or ∩-shape depends on the value of the constant [tex]a[/tex] that goes with [tex] x^{2} [/tex]. When [tex]a[/tex] is (+), the curve is U-shape. When [tex]a[/tex] (-), the curve is ∩-shape

Part C:

The symmetry line of the curve will pass through the vertex, hence the symmetry line is [tex]x=-7[/tex]

This function is shown in the diagram below




Ver imagen merlynthewhizz

to anyone who may be a lil' sus, the previous answer is correct.