College

Which of the following choices are equivalent to the expression below?

[tex]x^{\frac{5}{8}}[/tex]

A. [tex]\left(x^8\right)^{1 / 5}[/tex]

B. [tex]\sqrt[8]{x^5}[/tex]

C. [tex]\sqrt[5]{x^8}[/tex]

Answer :

We are given the expression

[tex]$$
x^{\frac{5}{8}},
$$[/tex]

and we need to determine which of the following choices are equivalent to it.

1. The first expression is directly

[tex]$$
x^{\frac{5}{8}},
$$[/tex]

which is exactly the same as the given expression.

2. The second expression is

[tex]$$
\left(x^8\right)^{\frac{1}{5}}.
$$[/tex]

By using the power rule, where [tex]$\left(x^a\right)^b = x^{a \cdot b}$[/tex], we have

[tex]$$
\left(x^8\right)^{\frac{1}{5}} = x^{8 \cdot \frac{1}{5}} = x^{\frac{8}{5}}.
$$[/tex]

Since [tex]$\frac{8}{5} \neq \frac{5}{8}$[/tex], this option is not equivalent to the given expression.

3. The third expression is

[tex]$$
\sqrt[8]{x^5}.
$$[/tex]

The radical expression can be rewritten in exponential form as

[tex]$$
x^{\frac{5}{8}},
$$[/tex]

which is equivalent to the given expression.

4. The fourth expression is

[tex]$$
\sqrt[5]{x^8}.
$$[/tex]

Similarly, rewriting it in exponential form we have

[tex]$$
x^{\frac{8}{5}},
$$[/tex]

which is not equivalent to [tex]$x^{\frac{5}{8}}$[/tex].

Thus, we find that only two of the given expressions (the first and the third) are equivalent to [tex]$x^{\frac{5}{8}}$[/tex].

The final answer is therefore [tex]$\boxed{2}$[/tex].