Which of the following expressions are equivalent to [tex]$6^{-3}$[/tex]?

A. [tex]\frac{1}{6^3}[/tex]

B. [tex]\frac{1}{6^{-3}}[/tex]

C. [tex]\frac{1}{-216}[/tex]

D. [tex]\frac{1}{216}$



Answer :

To identify which of the given expressions are equivalent to [tex]\(6^{-3}\)[/tex], we first need to evaluate each expression and compare it with [tex]\(6^{-3}\)[/tex].

1. Evaluating [tex]\(6^{-3}\)[/tex]:

[tex]\[ 6^{-3} = \frac{1}{6^3} \][/tex]

To simplify [tex]\(6^{-3}\)[/tex], we need to understand that raising 6 to the power of [tex]\(-3\)[/tex] means taking the reciprocal of [tex]\(6^3\)[/tex].

[tex]\[ 6^3 = 6 \times 6 \times 6 = 216 \][/tex]

Therefore,

[tex]\[ 6^{-3} = \frac{1}{6^3} = \frac{1}{216} \][/tex]

2. Evaluating each given expression:

- [tex]\(\frac{1}{6^3}\)[/tex]:

[tex]\[ \frac{1}{6^3} = \frac{1}{216} \][/tex]

This matches [tex]\(6^{-3}\)[/tex].

- [tex]\(\frac{1}{6^{-3}}\)[/tex]:

Here, we take the reciprocal of [tex]\(6^{-3}\)[/tex].

[tex]\[ \frac{1}{6^{-3}} = 6^3 \][/tex]

Since [tex]\(6^{-3} = \frac{1}{216}\)[/tex], its reciprocal would be:

[tex]\[ 6^3 = 216 \][/tex]

This does not match [tex]\(6^{-3}\)[/tex].

- [tex]\(\frac{1}{-216}\)[/tex]:

This expression is simply the reciprocal of [tex]\(-216\)[/tex].

[tex]\[ \frac{1}{-216} = -\frac{1}{216} \][/tex]

This does not match [tex]\(6^{-3}\)[/tex], as it is the negative of [tex]\(\frac{1}{216}\)[/tex].

- [tex]\(\frac{1}{216}\)[/tex]:

This expression directly evaluates to:

[tex]\[ \frac{1}{216} \][/tex]

This matches [tex]\(6^{-3}\)[/tex].

3. Conclusion:

From the evaluations above, we can conclude that the expressions equivalent to [tex]\(6^{-3}\)[/tex] are:

[tex]\[ \frac{1}{6^3} \][/tex]
[tex]\[ \frac{1}{216} \][/tex]

Thus, the expressions that are equivalent to [tex]\(6^{-3}\)[/tex] are the first and the fourth ones.

So the final answer is:

[tex]\[ \boxed{1 \text{ and } 4} \][/tex]