Hi,

I have a simple question regarding solving a quadratic function

I tried to solve it as follows in general for y=y1 find the roots of the quadratic equation:

Hence, in more detail...

for :

assuming

However, this is not producing the desired result. For example, assume the following function

and following the solution above gives:

and

None of them being 3 as I would expect. Can someone point me in the right direction or a link with info I can look up?

Thank you in advance.