Get the answers you've been searching for with IDNLearn.com. Our platform is designed to provide trustworthy and thorough answers to any questions you may have.

Select the correct answer.

What is the simplified form of this expression?
[tex] \sqrt{8 x^3 + 24 x^2 + 18 x} [/tex]

A. [tex] \pm(2 x + 3) \sqrt{2 x} [/tex]

B. [tex] \pm(4 x + 6) \sqrt{2 x} [/tex]

C. [tex] \pm(2 x + 3) \sqrt{x} [/tex]

D. [tex] \pm(4 x + 6) \sqrt{x} [/tex]


Sagot :

To simplify the expression [tex]\(\sqrt{8x^3 + 24x^2 + 18x}\)[/tex], let's follow these steps:

1. Factor the expression inside the square root:
[tex]\[ 8x^3 + 24x^2 + 18x \][/tex]
We start by factoring out the greatest common factor (GCF) which is [tex]\(2x\)[/tex]:
[tex]\[ 8x^3 + 24x^2 + 18x = 2x(4x^2 + 12x + 9) \][/tex]

2. Further factor the quadratic expression:
We focus on factoring the quadratic [tex]\(4x^2 + 12x + 9\)[/tex]:
[tex]\[ 4x^2 + 12x + 9 = (2x + 3)^2 \][/tex]
Therefore:
[tex]\[ 8x^3 + 24x^2 + 18x = 2x(2x + 3)^2 \][/tex]

3. Take the square root of both sides:
[tex]\[ \sqrt{8x^3 + 24x^2 + 18x} = \sqrt{2x(2x + 3)^2} \][/tex]

4. Simplify the square root expression:
We know that the square root of a product equals the product of the square roots, hence:
[tex]\[ \sqrt{2x(2x + 3)^2} = \sqrt{2} \cdot \sqrt{x} \cdot \sqrt{(2x + 3)^2} \][/tex]
Since [tex]\(\sqrt{(2x + 3)^2} = |2x + 3|\)[/tex], we get:
[tex]\[ \sqrt{2} \cdot \sqrt{x} \cdot |2x + 3| \][/tex]
If [tex]\(2x + 3\)[/tex] is non-negative, then [tex]\(|2x + 3| = 2x + 3\)[/tex], and if [tex]\(2x + 3\)[/tex] is negative, [tex]\(|2x + 3| = -(2x + 3)\)[/tex]. Usually, in the context of real numbers, we use the positive root and include the [tex]\(\pm\)[/tex] sign to cover both cases.

Thus:
[tex]\[ \sqrt{2} \cdot \sqrt{x} \cdot |2x + 3| = \pm(2x + 3)\sqrt{2x} \][/tex]

Therefore, the correct answer is:
[tex]\[ \boxed{\pm(2x + 3)\sqrt{2x}} \][/tex]
Which corresponds to option A: [tex]\(\pm(2x + 3) \sqrt{2 x}\)[/tex].