Solve the Logarithmic Inequality: log₄x × log₅64 ≥ log₅(x³+x²+x+1)

Question

Given 0<X , find X

log4x×log564log5(x3+x2+x+1) \log_4x\times\log_564\ge\log_5(x^3+x^2+x+1)

Video Solution

Solution Steps

00:16 Let's solve this problem together.
00:21 We'll start by using the logarithm product formula. We may need to change between different bases, so keep that in mind.
00:33 Next, let's solve the given logarithm. Then we can substitute the result back into the exercise. Ready? Here we go.
01:03 We'll apply the power rule for logarithms. This means raising the number by the coefficient.
01:13 Now, let's compare the numbers in the logarithm. Doing great so far!
01:23 Let's simplify what we can. Reducing is like cleaning up your work and making it easier to see.
01:33 We'll use the root formula to find possible solutions. Keep in mind what we discussed about roots.
01:39 Remember, there are no roots less than zero.
01:43 Therefore, there is no solution to this question. And that's how we solve it!

Step-by-Step Solution

To solve this problem, we need to compare the expressions log4x×log564 \log_4 x \times \log_5 64 and log5(x3+x2+x+1)\log_5 (x^3 + x^2 + x + 1).

First, calculate log564 \log_5 64 . We know that 64=43=26 64 = 4^3 = 2^6 . Therefore:
log564=log526log54=6log522log52=3 \log_5 64 = \frac{\log_5 2^6}{\log_5 4} = \frac{6 \log_5 2}{2 \log_5 2} = 3

Next, simplify the left-hand side expression log4x \log_4 x . Using the change of base formula:
log4x=log5xlog54 \log_4 x = \frac{\log_5 x}{\log_5 4}

Therefore, the left-hand side becomes:
log5xlog54×3=3log5x2log52 \frac{\log_5 x}{\log_5 4} \times 3 = \frac{3 \log_5 x}{2 \log_5 2}

For the inequality:
3log5x2log52log5(x3+x2+x+1) \frac{3 \log_5 x}{2 \log_5 2} \ge \log_5 (x^3 + x^2 + x + 1)

We can now equate the right-hand side:
log5x3/2log52log5(x3+x2+x+1) \log_5 x^{3/2\log_5 2} \ge \log_5 (x^3 + x^2 + x + 1)

This implies:
x3/2log52x3+x2+x+1 x^{3/2\log_5 2} \ge x^3 + x^2 + x + 1

Testing and analyzing this expression results in no valid x x satisfying the inequality within real values since exponential growth and polynomial terms do not align. Thus, the inequality cannot be satisfied, and no solution satisfies the given conditions.

Therefore, the solution to the problem is: No solution.

Answer

No solution