I need to find units and zero divisors in $\mathbb{Q}[x]/{(x^2-1)}$.
I don't know how to start... I know that all elements in $\mathbb{Q[x]}/{(x^2-1)}$ are polynomials $p(x)= ax+b$ like $0, 1, x ,x+1$. Is there any way to find all elements in $\mathbb{Q[x]}/{(x^2-1)}$?