I have to find out the dimension of the solution of this set of the equations with the system being an affine space of $\Bbb R^4$ and $t∈R$, $u∈\Bbb R^4$.
So I tried to row reduce the left side of the system and found out that the rank is $4$ if $t≠0$ and $3$ if $t=0$. With the formula $\dim(L)=n-\operatorname*{rank}(A)$, I think that the dimension is $1$ for $t=0$ or $0$ for $t≠0$. But I am completely unsure if any of this is correct.
