y= X^2 + 9/x

Question

Find the value that gives the minimum or maximum value of y( ignoring x= 0).

Answer 1

Suppose you mean y = (x^2 + 9) / x

The maximum value of y is approached when x approaches zero from the right hand side.
The minimum value of y is approached when x approaches zero from the left hand side.

Note that neither value can ever truly be reached.

Suppose you mean y = x^2 + (9 / x) instead.

The maximum value of y is approached when x approaches zero from the right hand side, as well as when x approaches infinity or negative infinity.
The minimum value of y is approached when x approaches zero from the left hand side.

Once again, note that neither value can ever truly be reached.