Use the determinant feature of a graphing
utility to decide if the points
(−2,−6), (9, 1), (11, 2)
are collinear.
What is the value of the determinant?

Question

Use the determinant feature of a graphing
utility to decide if the points
(−2,−6), (9, 1), (11, 2)
are collinear.
What is the value of the determinant?

anonymous · Answer

So, if determinant of matrix A =0, they are collinear
what is A? A is a matrix of points and "1" column 
I mean $$A = \left[\begin {matrix}-1&-6&1\9&1&1\11&2&1\end{matrix}\right]$$
you can see the "1" column there. And det A = -3 $\neq 0$ therefore, the points are NOT collinear

anonymous · Answer

I just guess this is a problem from linear algebra. If it is so, then , my solution is valid. If it's graph theory problem, then, my solution is invalid.

anonymous · Answer

okay, why did you put -1 where 2 is supposed be? @OOOPS

anonymous · Answer

mistypo, sorry for that

anonymous · Answer

@OOOPS would I write 0 for my answer?