12
QuizMultiple Choice

Exponential and Logarithmic Functions: Part Two — Test

Question 12 • Advanced Algebra: Concepts and Connections

Which of the following shows the extraneous solution to the logarithmic equation? log sub 3 of open paren 18 x cubed close paren minus log sub 3 of 2 x is equal to the log base 3 of 144

Answer
A
x is equal to negative 8
B
x is equal to negative 4
C
x is equal to negative 2
D
x is equal to negative 16

Explanation

Combine the logarithms using the quotient rule: log₃(18x³) − log₃(2x) = log₃(9x²). Since the logarithms are equal, 9x² = 144, so x² = 16 and the algebraic solutions are x = 4 and x = −4. But the original logarithms require x > 0, so −4 is extraneous; the correct choice is x = −4.

AI-written and checked against the verified answer.

Previous
Next