Westonci.ca is the Q&A platform that connects you with experts who provide accurate and detailed answers. Discover a wealth of knowledge from professionals across various disciplines on our user-friendly Q&A platform. Get immediate and reliable solutions to your questions from a community of experienced professionals on our platform.

Which shows how to find the value of this expression when [tex] x = -2 [/tex] and [tex] y = 5 [/tex]?

[tex] \left(3 x^3 y^{-2}\right)^2 [/tex]

A. [tex] \frac{3^2(-2)^6}{5^4} [/tex]

B. [tex] \frac{3(-2)^6}{5^4} [/tex]

C. [tex] \frac{3^2(5)^6}{(-2)^4} [/tex]

D. [tex] \frac{3}{(2)^6 5^4} [/tex]


Sagot :

To determine the value of the expression \(\left(3 x^3 y^{-2}\right)^2\) for \(x = -2\) and \(y = 5\), let's go through the problem step-by-step.

### Step 1: Substitute the Values
First, substitute \(x = -2\) and \(y = 5\) into the expression:

[tex]\[ \left(3 (-2)^3 5^{-2}\right)^2 \][/tex]

### Step 2: Evaluate Inside the Parentheses
Evaluate the individual terms inside the parentheses:

- Calculate \((-2)^3\):
[tex]\[ (-2)^3 = -8 \][/tex]

- Calculate \(5^{-2}\) which is the same as \(\frac{1}{5^2}\):
[tex]\[ 5^{-2} = \frac{1}{25} \][/tex]

### Step 3: Combine the Results
Next, multiply these results together along with the constant coefficient 3:

[tex]\[ 3 \cdot (-8) \cdot \frac{1}{25} = 3 \cdot -8 \cdot 0.04 = -0.96 \][/tex]

So inside the parentheses we have:
[tex]\[ (3 (-2)^3 5^{-2}) = -0.96 \][/tex]

### Step 4: Square the Result
We now square the result obtained in the previous step:

[tex]\[ (-0.96)^2 = 0.9216 \][/tex]

### Step 5: Identify the Correct Choice
We need to find which of the given multiple-choice options match the numeric result of \(0.9216\). Let's simplify each option step-by-step to see which equals the computed result:

1. \(\frac{3^2(-2)^6}{5^4}\):
[tex]\[ 3^2 = 9 \][/tex]
[tex]\[ (-2)^6 = 64 \][/tex]
[tex]\[ 5^4 = 625 \][/tex]
[tex]\[ \frac{9 \cdot 64}{625} = \frac{576}{625} = 0.9216 \][/tex]

2. \(\frac{3(-2)^6}{5^4}\):
[tex]\[ 3 \cdot 64 = 192 \][/tex]
[tex]\[ \frac{192}{625} \approx 0.3072 \neq 0.9216 \][/tex]

3. \(\frac{3^2(5)^6}{(-2)^4}\):
[tex]\[ 3^2 = 9 \][/tex]
[tex]\[ 5^6 = 15625 \][/tex]
[tex]\[ (-2)^4 = 16 \][/tex]
[tex]\[ \frac{9 \cdot 15625}{16} = 87812.5 \neq 0.9216 \][/tex]

4. \(\frac{3}{(2)^6 5^4}\):
[tex]\[ (2)^6 = 64 \][/tex]
[tex]\[ 5^4 = 625 \][/tex]
[tex]\[ 64 \cdot 625 = 40000 \][/tex]
[tex]\[ \frac{3}{40000} = 0.000075 \neq 0.9216 \][/tex]

Thus, the correct choice is:
[tex]\[ \frac{3^2(-2)^6}{5^4} \][/tex]


So, the final answer is:
[tex]\[ \boxed{\frac{3^2(-2)^6}{5^4}} \][/tex]