Question 8627
The discriminant is the value {{{sqrt(b^2 - 4ac)}}} where a, b, and c are the coefficients of the quadratic equation in the standard form {{{ax^2+bx+c}}}.
This means you want to first rearrange the equation you have to standard form.
{{{5n^2=4n+6}}}
{{{5n^2 -4n-6=0}}} [adding -4n-6 to both sides]
So, a=5, b=-4, and c=-6
The discriminant is {{{sqrt(((-4)(-4)) - ((4)(5)(-6)))}}}
which is {{{sqrt(16+120)=sqrt(136)=11.66}}} or so.

This tells you that the solutions of the equation are both real.
This is clear also from the graph of the equation
{{{graph(500, 500, -5, 5, -10, 10, 5x^2-4x-6)}}}