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What is the following product? Assume [tex]$x \geq 0$[/tex].

[tex]
\left(4 x \sqrt{5 x^2}+2 x^2 \sqrt{6}\right)^2
[/tex]

A. [tex]104 x^4+8 x^4 \sqrt{30 x}[/tex]

B. [tex]80 x^6+8 x^5+8 x^5 \sqrt{30}+24 x^4[/tex]

C. [tex]104 x^6[/tex]

D. [tex]104 x^4+16 x^4 \sqrt{30}[/tex]


Sagot :

To find the square of the given expression [tex]\((4 x \sqrt{5 x^2} + 2 x^2 \sqrt{6})^2\)[/tex], let's break it down and simplify step-by-step.

1. Understand the individual terms inside the expression:
[tex]\[ 4 x \sqrt{5 x^2} + 2 x^2 \sqrt{6} \][/tex]

2. Simplify [tex]\( \sqrt{5 x^2} \)[/tex]:
[tex]\[ \sqrt{5 x^2} = x \sqrt{5} \quad \text{(since \(x \geq 0\))} \][/tex]

3. Substitute back into the expression:
[tex]\[ 4 x \sqrt{5 x^2} = 4 x \cdot x \sqrt{5} = 4 x^2 \sqrt{5} \][/tex]
So, the expression becomes:
[tex]\[ 4 x^2 \sqrt{5} + 2 x^2 \sqrt{6} \][/tex]

4. Factor out the common term [tex]\(2 x^2\)[/tex]:
[tex]\[ 2 x^2 (2 \sqrt{5} + \sqrt{6}) \][/tex]

5. Square the entire expression:
[tex]\[ (2 x^2 (2 \sqrt{5} + \sqrt{6}))^2 \][/tex]

6. Apply the square to each part of the product:
[tex]\[ (2 x^2)^2 \cdot (2 \sqrt{5} + \sqrt{6})^2 \][/tex]
[tex]\[ 4 x^4 \cdot (2 \sqrt{5} + \sqrt{6})^2 \][/tex]

7. Expand the binomial [tex]\((2 \sqrt{5} + \sqrt{6})^2\)[/tex]:
[tex]\[ (2 \sqrt{5} + \sqrt{6})^2 = (2 \sqrt{5})^2 + 2 \cdot (2 \sqrt{5}) \cdot (\sqrt{6}) + (\sqrt{6})^2 \][/tex]
[tex]\[ = 4 \cdot 5 + 2 \cdot 2 \sqrt{5} \cdot \sqrt{6} + 6 \][/tex]
[tex]\[ = 20 + 4 \sqrt{30} + 6 \][/tex]
[tex]\[ = 26 + 4 \sqrt{30} \][/tex]

8. Combine these results:
[tex]\[ 4 x^4 \cdot (26 + 4 \sqrt{30}) \][/tex]

9. Distribute [tex]\(4 x^4\)[/tex] through the terms inside the parentheses:
[tex]\[ 4 x^4 \cdot 26 + 4 x^4 \cdot 4 \sqrt{30} \][/tex]
[tex]\[ 104 x^4 + 16 x^4 \sqrt{30} \][/tex]

Therefore, the simplified form of [tex]\( (4 x \sqrt{5 x^2} + 2 x^2 \sqrt{6})^2 \)[/tex] is:
[tex]\[ 104 x^4 + 16 x^4 \sqrt{30} \][/tex]

Thus, the correct option is:
[tex]\[ 104 x^4 + 16 x^4 \sqrt{30} \][/tex]

So, the answer is the fourth option: [tex]\( \boxed{104 x^4 + 16 x^4 \sqrt{30}} \)[/tex].