Select the correct answer.

If [tex]f(x)=x-6[/tex] and [tex]g(x)=x^{\frac{1}{2}}(x+3)[/tex], find [tex]g(x) \times f(x)[/tex].

A. [tex]\sqrt[5]{x^2}-3 \sqrt[3]{x^2}-18 x^{\frac{1}{2}}[/tex]
B. [tex]\sqrt{x^5}-3 \sqrt{x^3}-18 \sqrt{x}[/tex]
C. [tex]\sqrt{x^5}-\sqrt{x^3}-6 \sqrt{x}[/tex]
D. [tex]\sqrt{x^5}-3 x^3-18 \sqrt{x}[/tex]



Answer :

To solve this problem, let’s start by finding the product of the functions [tex]\( f(x) \)[/tex] and [tex]\( g(x) \)[/tex]. Given:
[tex]\[ f(x) = x - 6 \][/tex]
[tex]\[ g(x) = x^{\frac{1}{2}}(x + 3) \][/tex]

First, we simplify [tex]\( g(x) \)[/tex]:
[tex]\[ g(x) = x^{\frac{1}{2}} \cdot (x + 3) \][/tex]
[tex]\[ g(x) = x^{\frac{1}{2}} \cdot x + x^{\frac{1}{2}} \cdot 3 \][/tex]
[tex]\[ g(x) = x^{1 + \frac{1}{2}} + 3x^{\frac{1}{2}} \][/tex]
[tex]\[ g(x) = x^{\frac{3}{2}} + 3x^{\frac{1}{2}} \][/tex]

Next, we find the product [tex]\( g(x) \times f(x) \)[/tex]:
[tex]\[ g(x) \times f(x) = (x^{\frac{3}{2}} + 3x^{\frac{1}{2}}) \times (x - 6) \][/tex]

We use the distributive property to simplify this expression:
[tex]\[ g(x) \times f(x) = x^{\frac{3}{2}} \cdot x + x^{\frac{3}{2}} \cdot (-6) + 3x^{\frac{1}{2}} \cdot x + 3x^{\frac{1}{2}} \cdot (-6) \][/tex]
[tex]\[ g(x) \times f(x) = x^{\frac{5}{2}} - 6x^{\frac{3}{2}} + 3x^{\frac{3}{2}} - 18x^{\frac{1}{2}} \][/tex]
[tex]\[ g(x) \times f(x) = x^{\frac{5}{2}} - 3x^{\frac{3}{2}} - 18x^{\frac{1}{2}} \][/tex]

To express the terms with exponents in a common form, note that:
[tex]\[ x^{\frac{5}{2}} = \sqrt{x^5} \][/tex]
[tex]\[ x^{\frac{3}{2}} = \sqrt{x^3} \][/tex]
[tex]\[ x^{\frac{1}{2}} = \sqrt{x} \][/tex]

Thus, the expression simplifies to:
[tex]\[ g(x) \times f(x) = \sqrt{x^5} - 3\sqrt{x^3} - 18\sqrt{x} \][/tex]

The correct answer is:
B. [tex]\(\sqrt{x^5} - 3\sqrt{x^3} - 18\sqrt{x}\)[/tex]