So, I was given a question which went like this

y=Quadratic/Quadratic, find range of y.

So, my teacher said that I needed to make a quadratic in x by taking all the terms in one side and then I had to make the discriminant greater than or equal to zero since x is real. But, discriminant is greater than or equal to zero when roots are real and distinct. So, I am unable to relate to that theory of quadratic equation.