82.4k views
2 votes
Does anyone know why this is the answer

Does anyone know why this is the answer-example-1
User Marged
by
8.0k points

1 Answer

9 votes

Answer:

h(x) = (x -1)(x -(3 +√2))(x -(3 -√2))

Explanation:

The given cubic is said to have 1 as a zero. That means (x -1) is a linear factor of the equation. Dividing the cubic by that using your favorite method gives a quotient that is the quadratic ...

x^2 -6x +7

We can write this in vertex form by "completing the square":

(x^2 -6x) +7

= (x^2 -6x +9) +7 -9 . . . . . add and subtract (-6/2)^2 = 9

= (x -3)^2 -2

This can be factored as the difference of two squares:

a² -b² = (a -b)(a +b)

Here we have ...

a² = (x-3)² ⇒ a = (x -3)

b² = 2 ⇒ b = √2

Then the linear factors of the quadratic are ...

x^2 -6x +7 = ((x -3) -√)((x -3) +√2)

= (x -(3 +√2))(x -(3 -√2)) . . . . . using the associative property of addition

And the cubic can be factored to linear factors as ...

h(x) = x^3 -7x^2 +13x -7

h(x) = (x -1)(x^2 -6x +7)

h(x) = (x -1)(x -(3 +√2))(x -(3 -√2))

Does anyone know why this is the answer-example-1
User Brent Eicher
by
8.9k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories