The range of y = x + x-3 / 1 (x is greater than 3) is determined by means inequality method

The range of y = x + x-3 / 1 (x is greater than 3) is determined by means inequality method

y=x-3 +1/(x-3) +3
≥2√(x-3)*1/(x-3) +3
=5
When x-3 = 1 / (x-3), i.e. x = 4