Let $A$ be a square matrix of order 2 such that $|A|=2$ and the sum of its diagonal elements is -3. If the points ( $x, y$ ) satisfying $A^2+x A+y I=0$ lie on a hyperbola, whose transverse axis is parallel to the x axis, eccentricity is e and the length of the latus rectum is $\ell$, then $\mathrm{e}^4+\ell^4$ is equal to