84 Given that the quadratic curve $x^{2}+x y+y=0$ is a hyperbola, then one of its asymptotes is ( )
A. $x=1$
B. $y=x-1$
C. $y=1-x$
D. $y=1$
84 C. Because
$$
x^{2}+x y+y=x(x+y)+y=(x+1)(x+y-1)+1 .
$$

So the equations of the two asymptotes are
$$
x+1=0 \text { and } x+y-1=0
$$