I know about collinear points (points lying on a same straight line).
I know about collinear vector (parallel vectors).
But, coming to collinear lines, I am not even able to imagine them, and I can't find any definition.
Exact Question I am dealing with is: $$\text{ [ The three straight lines ax+by=c,bx+cy=a and cx+ay=b are collinear, if ]}$$
One possible approach I did, Collinear lines have collinear points, which will have zero area, so while calculating area, I get $0=0$ identity.
So, kindly shed knowledge upon collinear lines.
PS: Googling the exact question gives the same answer on every site. They basically add the equations, and compare the coefficient.
First, I've not seen this usage in 65+ years of looking at mathematics... which leads me to suspect it's either a literal typo, or is a sort of word-typo, where the word that was intended was replaced by something similar.
Second, literally, "collinear" would tend to mean something like "on the same line", or "parallel", maybe, the latter for lines themselves?
But, we should admit/note that it is too ambiguous, and is not a good (=helpful) usage.