A doubt regarding on previous question

[XIPP]

Amit Sir, (or anyone who can solve this:)

As you asked here the equation sq(x) − 5|x| + 4 = 0, the solutions as answered by N Uday Kumar are 4,-4,1,-1. But the domain of the given equation doesn't allow negatives, we have only 1 and 4. But putting 4 in equation back, sq(4)-5|4|+4=2-20+4=(-14), which is not equal to 0. So the only solution is 1.

Wolfram|Alpha also confirms me!SEE This.

Where am I wrong? (Or why N Uday Kumar true?)

[duck]

Hi XIPP.. :)

In the question that Amit Sir asked , it was sq(x) = x^2.
And what you're asking is sqrt(x) =√x

[XIPP]

Oh sorry, sqtr vs sq! Nice.