\hsize 0pt
\vsize 0pt
\nopagenumbers
\overfullrule 0pt
\noindent
$$
\eqalign{
v(n) &= x(n) - \beta(1 + \alpha)v(n - 1) - \alpha v(n - 2)
\cr
y(n) &= \alpha v(n) + \beta(1 + \alpha) v(n - 1) + v(n - 2)
}
$$
\bye