I never played 2v2 matchups before but when i was doing ranked matches to figure where iw ould be placed i was constantly playing plats and golds, why is that?

Your ranked MMR is what determines who you are playing. You develop a ranked MMR by playing ranked. The game assumes that everyone starts at a static MMR (let's say 1000) and has a formula to determine what your MMR is approximately by playing you against other players, determining the expected outcome, and then comparing it with the real outcome.

So if your MMR is 1000, the game will try to match you with someone who has an MMR around 1000 as well. Let's say you lose that game--because you have a similar MMR, you will lose 100 points. You're down to 900. If you play another game against someone at 1000, the game expects you to lose, and so you'll lose fewer points--maybe just 80 this time. But let's say a 820 you beat someone at 1100 MMR...you'll gain a large number of points because you were not expected to win that game but did.

For the first few games, SC2 is trying to figure out where your approximate MMR is. You'll play a variety of different players from a variety of different leagues. If you're new, you'll probably lose all of these games--that's to be expected. Just keep plugging and you will get better.

i went 2-3 and ended up in gold, why did that happen?

If your opponents were gold & plats it would make sense that you would end up in gold.

Say, you lose twice to 2x plats, win vs 1 gold & 1 plat, lose to a gold.

Place you right around gold league, with a really loose MMR.

'cuz you went around .500 against plat and gold opponents?

Don't worry, if you're better/worse than where you got placed it'll all get sorted out quickly. Low number of games = high MMR volatility.

Yes yes, I really want to see their algorithm, it must be fucking awesome.

It's a modified Elo system. If you want to get the basics just look up the Elo system and you'll pretty much understand everything. Then they have a range algorithm to pick a valid player for you to match against.

I know its much like the ELO system, but I want to see the actual numbers of how they do it.

I like that shit.