I am trying to solve a quadratic equation with 2 variables to obtain minima or maxima points.
The equation I have is:
But when I solve this for global extrema points, using 2 partial derivative equation(keeping one variable constant at a time), I'm getting single value for $x$ but 2 values for $y$.
i.e. $x=2.3$ and $y=149.75$ and $162.15$. I'm not being able to understand if it is possible or I am making a mistake.
A little help with this matter will be highly appreciated.