What do R1 and R2 mean in matrices? (About augmented form and gaussian method)

Question

anonymous · Answer

Moreover I don't get this
(See attachment)
what happens after "using elementary operations) since before that it seemed that you can use the gaussian form [    |  ] where you have either nx or ny so that you can divide entire upper row by n   and for each value on lower row subtract from IT the value above it.

however this doesnt make any sense in how they choose what to divide by what

amistre64 · Answer

R1 and R2 refer to rows that are being worked about

amistre64 · Answer

there is no set way to do it, so they provide you with the way they choose to go about it

anonymous · Answer

Ooh I was just reasoning this wrong. I got it, thanks!

amistre64 · Answer

it is pretty basic once you understand what they are trying to convey ;)