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TMUAmockz Set 1 Paper 2 · Q12

Paper 2Powers & logarithmsNumber & countingAlgebra

A student claims that log⁡3(x−4)+log⁡3(22−x)<4\log_3(x-4)+\log_3(22-x)<4 holds for all integers xx with 4<x<224<x<22. Is the student correct? If not, state the integer values for which the inequality fails and find the total number of integers with 4<x<224<x<22 for which it does hold.

AThe student is correct; all 17 integers satisfy the inequality
BThe student is incorrect; the inequality fails for x=4x=4 and x=22x=22 only
CThe student is incorrect; the inequality fails for 2 integers
DThe student is incorrect; the inequality fails for exactly 1 integer, giving 16 valid values
EThe student is incorrect; the inequality fails for 3 integers
FThe student is incorrect; the inequality fails for 4 integers

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