\(M^2=\left(x-y\right)^2=\left(x+y\right)^2-4xy=5^2-4\cdot\left(-2\right)=25+8=33\)
nên \(\left[{}\begin{matrix}x-y=\sqrt{33}\\x-y=-\sqrt{33}\end{matrix}\right.\)
\(N=x^2-y^2=\left(x-y\right)\left(x+y\right)\)
\(=\left[{}\begin{matrix}-5\sqrt{33}\\5\sqrt{33}\end{matrix}\right.\)