If |x| > 3, which of the following must be true?
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17 Nov 2021, 19:29
\(|x| = \pm x\)
\(+x > 3\) and \(-x > 3 \Rightarrow x < 3\)
So I is false since there exist negative values of \(x\)
\(|x|^2 = (\pm x)^2 = x^2\)
\(x > 9 \Rightarrow x^2 > 3^2 \Rightarrow x^2 > 9\)
So, II is true
\(|x-1| > 2 \Rightarrow x-1 > 2\) & \(-x+1 > 2\)
\(x -1+1 > 2+1\) & \(-x+1-1>2-1\)
\(x > 3\) & \(-x>1 \Rightarrow x<1\)
\(x < 2\) is not always true.
So, III is false
Hence, Answer is B