Which expression is equivalent to [tex]\left(\frac{\left(2 a^{-3} b^4\right)^2}{\left(3 a^5 b\right)^{-2}}\right)^{-1}[/tex]? Assume [tex]a \neq 0, b \neq 0[/tex].

A. [tex]\frac{2}{3 a^4 b^{10}}[/tex]

B. [tex]\frac{4}{9 a^4 b^{10}}[/tex]

C. [tex]\frac{1}{36 a^4 b^{10}}[/tex]

D. [tex]\frac{36 a^4 b^{10}}{2}[/tex]



Answer :

To determine which expression is equivalent to [tex]\(\left(\frac{\left(2 a^{-3} b^4\right)^2}{\left(3 a^5 b\right)^{-2}}\right)^{-1}\)[/tex], let's simplify the expression step by step.

First, simplify the numerator and the denominator separately:

Numerator:

[tex]\[ (2 a^{-3} b^4)^2 \][/tex]

Using the properties of exponents, we can expand this:

[tex]\[ 2^2 \cdot (a^{-3})^2 \cdot (b^4)^2 = 4 \cdot a^{-6} \cdot b^8 \][/tex]

So, the simplified form of the numerator is:

[tex]\[ 4 a^{-6} b^8 \][/tex]

Denominator:

[tex]\[ (3 a^5 b)^{-2} \][/tex]

Again, using the properties of exponents:

[tex]\[ (3 a^5 b)^{-2} = 3^{-2} \cdot (a^5)^{-2} \cdot (b)^{-2} = \frac{1}{3^2} \cdot a^{-10} \cdot b^{-2} = \frac{1}{9} a^{-10} b^{-2} \][/tex]

Next, we substitute the simplified forms of the numerator and denominator back into the original expression:

[tex]\[ \frac{4 a^{-6} b^8}{\frac{1}{9} a^{-10} b^{-2}} \][/tex]

Simplifying further by multiplying by the reciprocal of the denominator:

[tex]\[ 4 a^{-6} b^8 \times 9 a^{10} b^2 = 4 \cdot 9 \cdot a^{-6+10} \cdot b^{8+2} = 36 a^4 b^{10} \][/tex]

Now, we need to take the reciprocal of this result because of the exponent [tex]\(-1\)[/tex]:

[tex]\[ \left(36 a^4 b^{10}\right)^{-1} = \frac{1}{36 a^4 b^{10}} \][/tex]

Thus, the given expression simplifies to:

[tex]\[ \frac{1}{36 a^4 b^{10}} \][/tex]

Comparing this result with the given options, the answer is:

[tex]\[ \boxed{\frac{1}{36 a^4 b^{10}}} \][/tex]

This corresponds to the third option.