v = F_MUL(f, v, u, y); /* %$B = A x^{-2} = x + a + b x^{-2}$% */
y = F_QUADSOLVE(f, y, v); /* %$z^2 + z = B$% */
if (y) y = F_MUL(f, y, y, x); /* %$y = z x$% */
v = F_MUL(f, v, u, y); /* %$B = A x^{-2} = x + a + b x^{-2}$% */
y = F_QUADSOLVE(f, y, v); /* %$z^2 + z = B$% */
if (y) y = F_MUL(f, y, y, x); /* %$y = z x$% */