Determine real number(s)for $a,b$ such that the system has no solution, has a unique solution, and has more than one solution: $$\begin{align*} x-2y+az-t&=1\\ -x+y-z+t&=-1\\ (a+1)y-a^2z+at&=0\\ (b+1)y-abz-a^2t&=b \end{align*}$$
I could not transform the matrix into row reduced form.So that I could not find $a$ and $b$. I will be glad if someone could solve it.