Floor drain backup source

[kathysart]

Resolved first sewer drain backup, but is happening again. What I originally did isn't working this time, but discovered that because of having to replace kitchen sink faucet, using bathroom to wash dishes, that I had no sewer drain backup using anything in the bathroom. Only when I used the kitchen sink again and did the laundry - which is part of the kitchen - that I once again had a sewer backup. I am a 66 year old woman who can do many things around the house, but plumbing is new to me. I am trying to understand the plumbing line system and whether there is some thing I can do in the kitchen sink or laundry room sink to resolve this problem since that seems to be where the problem is coming from. Can you snake plumbing lines in kitchen or laundry room? How do these lines run together with the rest of the plumbing lines?
I can't easily afford to call someone and sincerely believe you must be able to solve some of these problems yourself, unless you have lots of $. I learned to replace the kitchen faucet, so I think I can, also, do this. Any help greatly appreciated. House is 50 years old, which I inherited.

 

[Fred]

It's difficult to help with your issue unless you can see the layout. Normally I start by plunging the sink. If that doesn't work I remove the trap & cleaning that out. Then if that doesn't work snake the drain where the trap connects. In this case what is suspicious is that two drains are plugged. That could point to a clog in the main waste line or at least down stream of the two sinks. In that case I'd call a plumber.
How old is the house? What type of waste pipe do you have?