How am I supposed to carry if every time my team does litterly nothing productive?

I have been having trouble, it sees like every game in ranked or in every few in norms, I get these teams that act as if they do not even understand how to play league. I am in b5 so that is not too surprising but even in my placement games I got so many trolls and people who do not even understand how champions work. Every time I have looked for help in some way I am just told, oh play adc.... play mid.... it's all the same, some champions carry insane, for example I played draven adc for 8 of my placements, I lost 1 because of a trolling support, the other 2 I had to play a position I did not know well for ranked ( I lost that game) or I won as jhin, so 8/10 games and I got b5 ( 7/10 in season 5 and I got s2). 2-3 of those games I had 20 kills give or take, about 3-5 I had 10 give or take a few, mostly giving a few. So I want to know why I got b5, and how am I supposed to carry if every one but me feeds or is unproductive? Last norm I played I went 8/0/3 I couldn't do anything because my team fed the living hell out of a syndra, naut, & Nasus, I was warwick, the game was not too long, 30minutes. I am not too concerned about winning norms but the ranked games are driving me crazy, people a game not long ago, I was going to be jungle but was made to go shaco support after I locked. Sorry for all the details if they are too much, I will add a link to my account on lolking above.