Problem

Write as a Single Logarithm 2( log of 2x+ log of y)-( log of 3+2 log of 5)

The problem is asking you to take multiple logarithmic expressions that are combined with multiplication, division, and exponents (implied through the presence of coefficients in front of the logs), and simplify them into a single logarithmic expression. This requires the use of log properties such as the product rule, quotient rule, and power rule to combine the terms. The final answer should be a single log expression that mathematically is equivalent to the original combined expressions.

$2 \left(\right. log \left(\right. 2 x \left.\right) + log \left(\right. y \left.\right) \left.\right) - \left(\right. log \left(\right. 3 \left.\right) + 2 log \left(\right. 5 \left.\right) \left.\right)$

Answer

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Solution:

Step 1: Simplify each logarithmic term.

Step 1.1: Apply the product property of logarithms.

Using the product property $\log_b(x) + \log_b(y) = \log_b(xy)$, combine the logs:

$2 \log(2x) + 2 \log(y) - (\log(3) + 2 \log(5))$

Step 1.2: Use the coefficient rule to move the 2 inside the log.

Transform $2 \log(2xy)$ into $\log((2xy)^2)$:

$\log((2xy)^2) - (\log(3) + 2 \log(5))$

Step 1.3: Distribute the square over the product.

Apply the rule $(ab)^n = a^n b^n$:

$\log(2^2x^2y^2) - (\log(3) + 2 \log(5))$

Step 1.4: Calculate the square of 2.

Compute $2^2$:

$\log(4x^2y^2) - (\log(3) + 2 \log(5))$

Step 1.5: Simplify the remaining terms.
Step 1.5.1: Move the 2 inside the log for $\log(5)$.

Convert $2 \log(5)$ to $\log(5^2)$:

$\log(4x^2y^2) - (\log(3) + \log(25))$

Step 1.5.2: Calculate the square of 5.

Compute $5^2$:

$\log(4x^2y^2) - (\log(3) + \log(25))$

Step 1.6: Combine the logs with addition into a single log.

Use the product property again:

$\log(4x^2y^2) - \log(3 \cdot 25)$

Step 1.7: Multiply 3 by 25.

Calculate $3 \cdot 25$:

$\log(4x^2y^2) - \log(75)$

Step 2: Use the quotient property of logarithms.

Apply the quotient property $\log_b(x) - \log_b(y) = \log_b(\frac{x}{y})$ to combine the logs into a single logarithm:

$\log\left(\frac{4x^2y^2}{75}\right)$

Knowledge Notes:

  1. Product Property of Logarithms: For any positive numbers $x$ and $y$ and any positive base $b$ (where $b \neq 1$), the logarithm of a product is the sum of the logarithms: $\log_b(xy) = \log_b(x) + \log_b(y)$.

  2. Quotient Property of Logarithms: For any positive numbers $x$ and $y$ and any positive base $b$ (where $b \neq 1$), the logarithm of a quotient is the difference of the logarithms: $\log_b\left(\frac{x}{y}\right) = \log_b(x) - \log_b(y)$.

  3. Power Rule of Logarithms: For any positive number $x$, any positive base $b$ (where $b \neq 1$), and any real number $n$, the logarithm of a power is the product of the exponent and the logarithm: $\log_b(x^n) = n \log_b(x)$.

  4. Exponent Rules: The power of a product rule states that $(ab)^n = a^n b^n$, and the power of a power rule states that $(a^n)^m = a^{nm}$.

  5. Combining Logarithms: When simplifying logarithmic expressions, it is often useful to combine multiple logarithms into a single logarithm using the product, quotient, and power rules. This is particularly helpful when solving equations involving logarithms or when trying to express a logarithmic relationship in a simpler form.

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