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Solve the following logarithmic equations.
log2(9x^2 + 30x + 25) = 8

User Icj
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1 Answer

3 votes

Answer: No real solution

Explanation:

log₂(9x² + 30x + 25) = 8

we know that ㏒ₐx = b ⇔ aᵇ = x with a>0 and ≠1 and x >0. This way,

9x² + 30x + 25 = 2⁸

9x² + 30x + 25 = 256

9x² + 30x + 25 - 256 = 0

9x² + 30x - 231 = 0

Δ = 30²-4.9.231 = -7416

No real solution.

Log existence condition:

9x² + 30x + 25 > 0

Δ = 30²-4.9.25 = 0

x = -30/18 = -5/3 = -1.667

x ≠ -5/3

User Saus
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