Solve log₄x > 7log₄2: Base-4 Logarithmic Inequality

Question

7\log_42<\log_4x

Video Solution

Solution Steps

00:00 Solve
00:05 We will use the logarithm formula of power, raise the number by the coefficient
00:25 We will equate the logarithms
00:34 And this is the solution to the question

Step-by-Step Solution

To solve the inequality 7log42<log4x7\log_4 2 < \log_4 x, we will follow these steps:

  • Step 1: Simplify 7log427\log_4 2 using the logarithm properties.
  • Step 2: Write the inequality log4(27)<log4x\log_4(2^7) < \log_4 x.
  • Step 3: Solve for xx by converting the logarithmic inequality into an exponential form.

Let's now proceed with these steps:

Step 1: Using the power property of logarithms, we have 7log42=log4(27)7\log_4 2 = \log_4 (2^7). This step simplifies the multiplication into a single logarithmic term.

Step 2: Using substitution in the inequality, we write it as log4(27)<log4x\log_4 (2^7) < \log_4 x.

Step 3: Since logarithms are one-to-one functions, we can conclude that if log4(27)<log4x\log_4 (2^7) < \log_4 x, then 27<x2^7 < x. This results from the property ac=ad    c=da^c = a^d \iff c = d where the bases are equal.

Therefore, the solution to the inequality is 27<x\mathbf{2^7 < x}.

Answer

2^7 < x