The standard form of the equation of a parabola is [tex]y = x^2 - 6x + 14[/tex]. What is the vertex form of the equation?

A. [tex]y = (x - 3)^2 + 5[/tex]

B. [tex]y = (x - 3)^2 + 15[/tex]

C. [tex]y = (x + 3)(x - 3) + 5[/tex]

D. [tex]y = (x - 3)^2 + 23[/tex]



Answer :

To convert the quadratic equation from its standard form [tex]\( y = x^2 - 6x + 14 \)[/tex] to its vertex form, we need to complete the square. Let's go through this step-by-step:

1. Start with the given standard form:
[tex]\[ y = x^2 - 6x + 14 \][/tex]

2. Isolate the [tex]\( x \)[/tex] terms:
[tex]\[ y - 14 = x^2 - 6x \][/tex]

3. Complete the square on the right-hand side:
- Take the coefficient of [tex]\( x \)[/tex], which is [tex]\(-6\)[/tex], divide it by 2, and then square it.
[tex]\[ \left(\frac{-6}{2}\right)^2 = (-3)^2 = 9 \][/tex]
- Add and subtract this square inside the equation to maintain equality.
[tex]\[ y - 14 + 9 = x^2 - 6x + 9 \][/tex]

4. Simplify the equation:
- Combine constants on the left-hand side:
[tex]\[ y - 5 = x^2 - 6x + 9 \][/tex]
- Recognize that [tex]\( x^2 - 6x + 9 \)[/tex] is a perfect square trinomial, which can be expressed as [tex]\( (x - 3)^2 \)[/tex]:
[tex]\[ y - 5 = (x - 3)^2 \][/tex]

5. Isolate [tex]\( y \)[/tex] to write in vertex form:
[tex]\[ y = (x - 3)^2 + 5 \][/tex]

So, the vertex form of the given quadratic equation [tex]\( y = x^2 - 6x + 14 \)[/tex] is:

[tex]\[ y = (x - 3)^2 + 5 \][/tex]

Comparing this with the given choices, the correct answer is:

A. [tex]\( y = (x - 3)^2 + 5 \)[/tex]