A6. The equation of a line that has a zero at $x=-1$ is:
(A) $y=x-1$
(B) $y=2 x-2$
(C) $y=-1 x$
(D) $\frac{x}{-1}+\frac{y}{1}=-1$
(E) $6 y+3 x+3=0$
A6. To calculate the zero of a line, we consider the condition $y=0$. The line $6 y+3 x+3=0$ has a zero at $x=-1$.