Then x 2 = m+4.
So y = x 2+ 1/(x 2-4)
= m + 4 + 1/m
= (m + 1/m) + 4
& gt= 2 + 4 = 6
Take the equal sign if and only if m =1/m.
At this time, m 2 = 1, that is, x 2-4 = 1.
Because x > 2, x = root number 5 at this time.
That is, when x= root number 5, the minimum value of y is 6.