Which is the value of this expression when [tex]a=-2[/tex] and [tex]b=-3[/tex]?

[tex]\[
\left(\frac{3 a^{-3} b^2}{2 a^{-1} b^0}\right)^2
\][/tex]

A. [tex]\(\frac{4}{9}\)[/tex]

B. [tex]\(\frac{27}{8}\)[/tex]

C. [tex]\(\frac{243}{32}\)[/tex]

D. [tex]\(\frac{729}{64}\)[/tex]



Answer :

To solve the given expression when [tex]\( a = -2 \)[/tex] and [tex]\( b = -3 \)[/tex], we need to evaluate it step by step:

The expression is:
[tex]\[ \left(\frac{3 a^{-3} b^2}{2 a^{-1} b^0}\right)^2 \][/tex]

We'll break it down into parts:

1. Evaluate the numerator [tex]\( 3 a^{-3} b^2 \)[/tex]:
- First, compute [tex]\( a^{-3} \)[/tex]:
[tex]\[ a^{-3} = (-2)^{-3} = -\frac{1}{8} \][/tex]
- Compute [tex]\( b^2 \)[/tex]:
[tex]\[ b^2 = (-3)^2 = 9 \][/tex]
- Multiply these results with 3:
[tex]\[ 3 a^{-3} b^2 = 3 \times \left(-\frac{1}{8}\right) \times 9 = 3 \times -\frac{9}{8} = -\frac{27}{8} = -3.375 \][/tex]

2. Evaluate the denominator [tex]\( 2 a^{-1} b^0 \)[/tex]:
- First, compute [tex]\( a^{-1} \)[/tex]:
[tex]\[ a^{-1} = (-2)^{-1} = -\frac{1}{2} \][/tex]
- Compute [tex]\( b^0 \)[/tex]:
[tex]\[ b^0 = 1 \][/tex]
- Multiply these results with 2:
[tex]\[ 2 a^{-1} b^0 = 2 \times \left(-\frac{1}{2}\right) \times 1 = 2 \times -\frac{1}{2} = -1 \][/tex]

3. Form the fraction/numerator [tex]\( \frac{3 a^{-3} b^2}{2 a^{-1} b^0} \)[/tex]:
[tex]\[ \frac{3 a^{-3} b^2}{2 a^{-1} b^0} = \frac{-3.375}{-1} = 3.375 \][/tex]

4. Square the result:
[tex]\[ \left(\frac{3 a^{-3} b^2}{2 a^{-1} b^0}\right)^2 = (3.375)^2 = 11.390625 \][/tex]

Thus, the value of the given expression when [tex]\( a = -2 \)[/tex] and [tex]\( b = -3 \)[/tex] is:
[tex]\[ 11.390625 \][/tex]

To match this result with the provided options, we note:
[tex]\[ 11.390625 = \frac{729}{64} \][/tex]
so the correct answer is:
[tex]\[ \boxed{\frac{729}{64}} \][/tex]