Which inequality represents all values of [tex]\( x \)[/tex] for which the product is defined?

[tex]\[
\sqrt{5x} \cdot \sqrt{x+3}
\][/tex]

A. [tex]\( x \geq -3 \)[/tex]

B. [tex]\( x \geq 0 \)[/tex]

C. [tex]\( x \leq -3 \)[/tex]

D. [tex]\( x \ \textgreater \ 0 \)[/tex]



Answer :

To determine which inequality represents all values of [tex]\( x \)[/tex] for which the product [tex]\(\sqrt{5x} \cdot \sqrt{x+3}\)[/tex] is defined, we need to consider the conditions under which each square root expression is defined.

1. First Expression: [tex]\(\sqrt{5x}\)[/tex]

A square root [tex]\(\sqrt{5x}\)[/tex] is defined only when the expression inside the square root is non-negative. So, we need:
[tex]\[ 5x \geq 0 \][/tex]
Dividing both sides by 5:
[tex]\[ x \geq 0 \][/tex]

2. Second Expression: [tex]\(\sqrt{x+3}\)[/tex]

Similarly, the square root [tex]\(\sqrt{x+3}\)[/tex] is defined only when the expression inside is non-negative. Thus, we need:
[tex]\[ x+3 \geq 0 \][/tex]
Subtracting 3 from both sides:
[tex]\[ x \geq -3 \][/tex]

3. Combining the Inequalities

The product [tex]\(\sqrt{5x} \cdot \sqrt{x+3}\)[/tex] is only defined if both individual square roots are defined. Therefore, [tex]\( x \)[/tex] must satisfy both inequalities simultaneously:
[tex]\[ x \geq 0 \quad \text{and} \quad x \geq -3 \][/tex]

The more restrictive condition here is [tex]\( x \geq 0 \)[/tex]. In other words, if [tex]\( x \geq 0 \)[/tex], then it automatically satisfies the [tex]\( x \geq -3 \)[/tex] condition as well.

Therefore, the inequality that represents all values of [tex]\( x \)[/tex] for which the product [tex]\(\sqrt{5x} \cdot \sqrt{x+3}\)[/tex] is defined is:
[tex]\[ \boxed{x \geq 0} \][/tex]

So, the correct answer is:
[tex]\[ \boxed{B} \][/tex]

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