Question

Find the scope of sqrt4( 4 - x - sqrt( 6x -x^2 + 16 ) )
More inside.

Answer 1

There are 2 cases, where the inner square root is negative or when the outer 4 root is negative, I've already found where the first one is negative by doing \[6x - x^2 + 16 < 0\]

Then I try to solve the outer one by doing \[ (4-x) < \sqrt{6x-x^2 + 16}\] and I'm stuck in that point.