Question 41
Given the system of equations
$$
\begin{aligned} ax+(a-1)y&=1,\\ (a+1)x-ay&=1. \end{aligned}
$$
For which one of the following values of $a$ is there no solution for $x$ and $y?$
$$
\begin{aligned} ax+(a-1)y&=1,\\ (a+1)x-ay&=1. \end{aligned}
$$
For which one of the following values of $a$ is there no solution for $x$ and $y?$