Is the following equation quadratic?

$n^3-n+4=n^3$

$a{x}^2+bx+c=0$ where $a\ne 0$.

 
The equation $n^3-n+4=n^3$ can be framed as $-n+4=0$ by subtracting $n^3$ on both sides,
Thus, it is not a quadratic equation as it is not an equation of degree $2.$