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5. Find the LCM of ² - 81 and ² - 12x + 27. (x + 9) (x − 9) (x+3) (x - 9) (x − 3) (x +9) (x 9) (x − 3) (x - 9)​

User LoukasPap
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1 Answer

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The LCM of
(x^2 -81) and
(x^2 -12x+27) is (x+9)(x−9)(x−3), which matches option 4: (x+9)(x−9)(x−3).

To find the LCM (Least Common Multiple) of the polynomials
x^2 -81 and
x^2 -12x+27, let's factorize these polynomials first:


x^2 -81 can be factorized using the difference of squares formula:


x^2 -81=(x+9)(x-9).


x^2 -12x+27 factors as a perfect square trinomial:


x^2 -12x+27=(x-3)(x-9).

Now, to find the LCM, we need to consider each factor and take the maximum power for each unique factor.

The factors in
x^2 -81 are (x+9) and (x−9).

The factors in
x^2 -12x+27 are (x−3) and (x−9).

The LCM will contain each unique factor raised to its highest power:

x+9 appears in both factorizations, so its highest power is x+9.

x−9 appears in both factorizations, so its highest power is x−9.

x−3 appears only in the factorization of
x^2 -12x+27, so it remains as x−3.

Therefore, the LCM of
(x^2 -81) and
(x^2 -12x+27) is (x+9)(x−9)(x−3), which matches option 4: (x+9)(x−9)(x−3).

Question

Find the LCM of (x^2-81) and(x^2-12x+27)

1. (x - 9)​

2. (x − 3) (x -9)

3. (x + 9) (x − 9) (x+3)

4. (x + 9) (x − 9) (x-3)

User Zuleyma
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6.9k points