Take the tour ×  This is my first question here, so please tell
me if the question is too trivial for this location. I have read
FAQ and I didn't find the rule against easy questions :)  I
should construct a system of linear equation similar to this
one:  $$\begin{align}x+2y & = 4 \\ 5x-y & = \frac15\end{align}$$
It is suggested that similarity should be in relation between
coefficients. All that I see is that if we put it in form
$y=ax+b$, it is true that $ab=-1$.  Any hints?  share|improve
this question Well, you could multiply both sides of the second
equation with $5$... otherwise, I don't understand what
"similarity" is supposed to mean here. BTW, please don't use
homework as the only tag for your question; it's meant to be
used with more "mathematical" tags. –  Ｊ. Ｍ. Sep 26 '11 at 18:15
Okay, so any 2x2 system with unique solution can be considered
similar to this one? –  1osmi Sep 26 '11 at 18:41 You might want
to introduce yourself to the notation $Ax=b$ with this example
where $A$ is a matrix $x, b$