Solve the Logarithmic Inequality: log₂3 - log₂(x+3) ≤ 8

Question

log23log2(x+3)8 \log_23-\log_2(x+3)\le8

Video Solution

Solution Steps

00:00 Solution
00:05 We'll use the logarithm subtraction formula, we'll get the logarithm of their ratio
00:14 We'll equate the logarithm numbers
00:29 We'll isolate X
00:37 And this is the solution to the question

Step-by-Step Solution

To solve this problem, we'll apply the properties of logarithms and inequality manipulation.

Initially, consider the given inequality:

log23log2(x+3)8 \log_2 3 - \log_2 (x + 3) \le 8

Using the quotient rule of logarithms, combine the logs:

log2(3x+3)8 \log_2 \left(\frac{3}{x + 3}\right) \le 8

The inequality log2(3x+3)8 \log_2 \left(\frac{3}{x + 3}\right) \le 8 can be rewritten by converting the logarithm to an exponential form:

3x+328 \frac{3}{x + 3} \le 2^8

Since 28=256 2^8 = 256 , substitute to get:

3x+3256 \frac{3}{x + 3} \le 256

To remove the fraction, multiply both sides by x+3 x + 3 , assuming x+3>0 x + 3 > 0 to maintain the inequality direction:

3256(x+3) 3 \le 256(x + 3)

Divide by 256 to isolate x+3 x+3 :

3256x+3 \frac{3}{256} \le x + 3

Subtract 3 from both sides to solve for x x :

x32563 x \ge \frac{3}{256} - 3

Given the problem's constraints about the positivity of the logarithm's argument, ensure x>3 x > -3 . Our derived inequality starts from x32563 x \ge \frac{3}{256} - 3 , which satisfies this, thus correctly addressing the domain assumptions.

In conclusion, the solution to the inequality is:

x32563 x \ge \frac{3}{256} - 3

Answer

x32563 x\ge\frac{3}{256}-3


Related Subjects