Which expression is equivalent to [tex]\( -2 \log_2 x + 4 \log_2 y + 4 \log_2 z \)[/tex] ?

A. [tex]\(\log_2 \left(\frac{x^2 y^4}{z^4}\right)\)[/tex]

B. [tex]\(\log_2 \left(\frac{y^4 z^4}{x^2}\right)\)[/tex]

C. [tex]\(\log_2 \left(\frac{y z^4}{x^2}\right)\)[/tex]

D. [tex]\(\log_2 \left(\frac{y z}{x}\right)^6\)[/tex]



Answer :

To determine which expression is equivalent to [tex]\(-2 \log_2 x + 4 \log_2 y + 4 \log_2 z\)[/tex], let's follow a detailed step-by-step simplification process.

### Step 1: Apply the Power Rule of Logarithms

The power rule of logarithms states that [tex]\(a \log_b(c) = \log_b(c^a)\)[/tex]. We'll apply this rule to each term separately:

1. [tex]\(-2 \log_2 x\)[/tex]:
[tex]\[ -2 \log_2 x = \log_2(x^{-2}) \][/tex]

2. [tex]\(4 \log_2 y\)[/tex]:
[tex]\[ 4 \log_2 y = \log_2(y^4) \][/tex]

3. [tex]\(4 \log_2 z\)[/tex]:
[tex]\[ 4 \log_2 z = \log_2(z^4) \][/tex]

After applying the power rule to each term, the expression becomes:
[tex]\[ \log_2(x^{-2}) + \log_2(y^4) + \log_2(z^4) \][/tex]

### Step 2: Apply the Addition Rule of Logarithms

The addition rule of logarithms states that [tex]\( \log_b(A) + \log_b(B) = \log_b(AB) \)[/tex]. We will combine the logarithms using this rule:

First, combine [tex]\(\log_2(x^{-2})\)[/tex] and [tex]\(\log_2(y^4)\)[/tex]:
[tex]\[ \log_2(x^{-2}) + \log_2(y^4) = \log_2(x^{-2} y^4) \][/tex]

Next, combine this result with [tex]\(\log_2(z^4)\)[/tex]:
[tex]\[ \log_2(x^{-2} y^4) + \log_2(z^4) = \log_2(x^{-2} y^4 z^4) \][/tex]

### Step 3: Simplify the Expression Inside the Logarithm

We combine the terms inside the logarithm:
[tex]\[ \log_2(x^{-2} y^4 z^4) \][/tex]

Recognize that [tex]\(x^{-2} = \frac{1}{x^2}\)[/tex]. Therefore, the expression inside the logarithm can be rewritten as:
[tex]\[ x^{-2} y^4 z^4 = \frac{y^4 z^4}{x^2} \][/tex]

Thus, the entire expression is:
[tex]\[ \log_2\left(\frac{y^4 z^4}{x^2}\right) \][/tex]

Therefore, the expression that is equivalent to [tex]\(-2 \log_2 x + 4 \log_2 y + 4 \log_2 z\)[/tex] is:
[tex]\[ \boxed{\log_2\left(\frac{y^4 z^4}{x^2}\right)} \][/tex]