Which expression is equivalent to [tex]\left(\frac{4 m n}{m^{-2} n^6}\right)^{-2}[/tex]? Assume [tex]m \neq 0, n \neq 0[/tex].

A. [tex]\frac{n^6}{16 m^8}[/tex]
B. [tex]\frac{n^{10}}{16 m^6}[/tex]
C. [tex]\frac{n^{10}}{8 m^8}[/tex]
D. [tex]\frac{4 m^3}{n^8}[/tex]



Answer :

To determine which expression is equivalent to [tex]\(\left(\frac{4 m n}{m^{-2} n^6}\right)^{-2}\)[/tex], we need to simplify the expression step by step.

1. Simplifying the inner fraction:
[tex]\[ \frac{4 m n}{m^{-2} n^6} \][/tex]
First, handle the negative exponent in the denominator. Recall that [tex]\(m^{-2} = \frac{1}{m^2}\)[/tex]:
[tex]\[ \frac{4 m n}{\frac{1}{m^2} n^6} = 4 m n \cdot \frac{m^2}{n^6} = 4 m^{1+2} \cdot \frac{n}{n^6} = 4 m^3 \cdot \frac{n}{n^6} = 4 m^3 \cdot n^{1-6} = 4 m^3 \cdot n^{-5} \][/tex]
So we have:
[tex]\[ 4 m^3 n^{-5} \][/tex]

2. Applying the negative exponent to the simplified expression:
[tex]\[ \left(4 m^3 n^{-5}\right)^{-2} \][/tex]
Recall the rule [tex]\((a \cdot b)^{-c} = a^{-c} \cdot b^{-c}\)[/tex]:
[tex]\[ \left(4 \cdot m^3 \cdot n^{-5}\right)^{-2} = 4^{-2} \cdot (m^3)^{-2} \cdot (n^{-5})^{-2} \][/tex]
Simplify each part:
[tex]\[ 4^{-2} = \frac{1}{4^2} = \frac{1}{16} \][/tex]
[tex]\[ (m^3)^{-2} = m^{3 \cdot -2} = m^{-6} \][/tex]
[tex]\[ (n^{-5})^{-2} = n^{-5 \cdot -2} = n^{10} \][/tex]

Combine these results:
[tex]\[ \frac{1}{16} \cdot m^{-6} \cdot n^{10} = \frac{n^{10}}{16 m^6} \][/tex]

Therefore, the expression equivalent to [tex]\(\left(\frac{4 m n}{m^{-2} n^6}\right)^{-2}\)[/tex] is:
[tex]\[ \boxed{\frac{n^{10}}{16 m^6}} \][/tex]