Math Problem Statement

3 * log_2(x) - 2 * log(5x) = 2

Solution

To solve the equation 3log2(x)2log(5x)=23 \cdot \log_2(x) - 2 \cdot \log(5x) = 2, we need to work through the following steps:

Step 1: Convert the logarithms to a common base

Given that the equation mixes base-2 logarithms with base-10 logarithms, it’s usually easiest to convert everything to the same base. Let's convert log2(x)\log_2(x) to base 10 using the change of base formula:

log2(x)=log(x)log(2)\log_2(x) = \frac{\log(x)}{\log(2)}

So, the equation becomes:

3log(x)log(2)2log(5x)=23 \cdot \frac{\log(x)}{\log(2)} - 2 \cdot \log(5x) = 2

Step 2: Simplify the equation

Distribute and simplify the terms:

3log(x)log(2)2log(5x)=2\frac{3 \cdot \log(x)}{\log(2)} - 2 \cdot \log(5x) = 2

Step 3: Express log(5x)\log(5x)

Recall that:

log(5x)=log(5)+log(x)\log(5x) = \log(5) + \log(x)

Substitute this back into the equation:

3log(x)log(2)2(log(5)+log(x))=2\frac{3 \cdot \log(x)}{\log(2)} - 2 \cdot \left(\log(5) + \log(x)\right) = 2

Expanding:

3log(x)log(2)2log(5)2log(x)=2\frac{3 \cdot \log(x)}{\log(2)} - 2 \cdot \log(5) - 2 \cdot \log(x) = 2

Step 4: Combine like terms

Group the log(x)\log(x) terms together:

(3log(2)2)log(x)=2+2log(5)\left(\frac{3}{\log(2)} - 2\right) \cdot \log(x) = 2 + 2 \cdot \log(5)

Step 5: Solve for log(x)\log(x)

Now isolate log(x)\log(x):

log(x)=2+2log(5)3log(2)2\log(x) = \frac{2 + 2 \cdot \log(5)}{\frac{3}{\log(2)} - 2}

Step 6: Calculate the value

Substitute log(2)0.3010\log(2) \approx 0.3010 and log(5)0.6990\log(5) \approx 0.6990:

log(x)=2+20.699030.30102\log(x) = \frac{2 + 2 \cdot 0.6990}{\frac{3}{0.3010} - 2}

Calculate:

log(x)=2+1.3989.96682\log(x) = \frac{2 + 1.398}{9.9668 - 2}

log(x)=3.3987.96680.4267\log(x) = \frac{3.398}{7.9668} \approx 0.4267

Finally, solve for xx:

x=100.42672.67x = 10^{0.4267} \approx 2.67

Final Answer:

The solution is approximately x2.67x \approx 2.67.


Do you want any details or have any questions?

Here are 5 related questions for further practice:

  1. Solve 2log3(x)+3log2(x)=52 \cdot \log_3(x) + 3 \cdot \log_2(x) = 5.
  2. Solve log4(x)+2log(x)=3\log_4(x) + 2 \cdot \log(x) = 3.
  3. What is the value of xx if 5log(x)log5(x2)=15 \cdot \log(x) - \log_5(x^2) = 1?
  4. Solve for xx in the equation log(x2)+log(x)=3\log(x^2) + \log(x) = 3.
  5. Find the value of xx in the equation 4log5(x)log5(x3)=14 \cdot \log_5(x) - \log_5(x^3) = 1.

Tip: Always consider converting logarithms to the same base when solving equations that mix different logarithmic bases.

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Math Problem Analysis

Mathematical Concepts

Algebra
Logarithms
Change of Base Formula

Formulas

Change of Base Formula: log_b(x) = log_c(x) / log_c(b)
Logarithm of a Product: log_b(xy) = log_b(x) + log_b(y)

Theorems

Change of Base Theorem
Properties of Logarithms

Suitable Grade Level

Grades 10-12