Hi again, came across this matrix question which has really got me stuck.

A = $\displaystyle \left(\begin{array}{cc}q&3\\-2&q-1\end{array}\right)$

1. Find det A, worked this out to be $\displaystyle q(q-1)+6$.

2. Show that A is non-singular for all values of q.

If it is non singular, then the det does not equal 0, I think? But how would I go about showing this, solve the quadratic equation in terms of q?

Thanks in advance