[tex]$
\begin{array}{l}
f(x)=\sqrt{3 x} \\
g(x)=\sqrt{48 x}
\end{array}
$[/tex]

Find [tex]$(f \cdot g)(x)$[/tex]. Assume [tex]$x \geq 0$[/tex].

A. [tex]$(f \cdot g)(x)=\sqrt{51 x}$[/tex]

B. [tex]$(f \cdot g)(x)=12 \sqrt{x}$[/tex]

C. [tex]$(f \cdot g)(x)=12 x$[/tex]

D. [tex]$(f \cdot g)(x)=72 x$[/tex]



Answer :

To determine [tex]\((f \cdot g)(x)\)[/tex] where [tex]\( f(x) = \sqrt{3x} \)[/tex] and [tex]\( g(x) = \sqrt{48x} \)[/tex], let's follow these steps:

1. Write the product function:
We are asked to find [tex]\( (f \cdot g)(x) \)[/tex], which means multiplying [tex]\( f(x) \)[/tex] and [tex]\( g(x) \)[/tex]:
[tex]\[ (f \cdot g)(x) = f(x) \cdot g(x) = \sqrt{3x} \cdot \sqrt{48x} \][/tex]

2. Utilize properties of square roots:
Recall that the product of square roots can be combined under a single square root:
[tex]\[ \sqrt{a} \cdot \sqrt{b} = \sqrt{a \cdot b} \][/tex]

3. Combine under one square root:
Apply this property to our product:
[tex]\[ (f \cdot g)(x) = \sqrt{3x} \cdot \sqrt{48x} = \sqrt{(3x) \cdot (48x)} \][/tex]

4. Simplify the expression inside the square root:
Multiply the constants and [tex]\(x\)[/tex]:
[tex]\[ (3x) \cdot (48x) = 144x^2 \][/tex]

5. Simplify the square root:
Evaluate the square root of [tex]\( 144x^2 \)[/tex]:
[tex]\[ \sqrt{144x^2} = \sqrt{144} \cdot \sqrt{x^2} = 12 \cdot x = 12x \][/tex]

Therefore, [tex]\((f \cdot g)(x) = 12x\)[/tex].

So, the correct answer is:
[tex]\[ \boxed{12x} \][/tex]