The expression x4 – 8x2 + m will be a perfect square when the value of m is:
Answer & explanation
Correct answer: option 2
When x4 – 8x2 + m is a perfect square then m must be a square also.
So, if we go through the options only 2nd and fourth options are the perfect square that are 16 and 4.
So if we take 16 , x4 – 8x2 + 16 is the square of (x2 + 4)2
The answer is m = 16.