If (x − ) = 6, and x > 0, find the value of (x² - ).
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 12.
Given that
If (x − ) = 6, and x > 0,
Squaring both sides
⇒ x2 + 1/x2 - 2 = 36
Adding 4 on both sides
⇒ x2 + 1/x2 - 2 + 4 = 36 + 4 = 40
⇒ (x + 1/x)2 = 40
⇒ x + 1/x = 2
Hence, the value of (x² - ) = (x + 1/x) (x - 1/x) = 2 × 6 = 12