The sentences are correct apart from a few gramatical errors: - The past participle of "to find" is "found", not "finded". - The second sentence should be "we were deciding whether or not to buy a house." "Determined" would only be okay if talking in the sense of "we determined that the best option for us was to buy a house." Otherwise, whilst it can still be used here, it sounds quite unnatural in the sentence. - "Can we decide a new term for the meeting" would be the correct one to use here, however "term" would sound much better if replaced with the word "topic", or perhaps "purpose" if you want to imply a new meaning for the meeting. We usually use the word "determine" to state that something has had a particular effect on something else, for example: the time you cook the chicken for determines whether or not it's okay to eat. It can also be used in the sense of discovering something, like what you mentioned in your first example, so for example: Scientists have determined that the risk of cancer in old people is very high. If you're determined to do something, however, you can also use the word (it implies that you have a strong desire and nothing will stop you), for example: I'm determined to finish my homework before dinner. I hope I've helped you in some way!

I would say it means to come to a conclusion, or to decide on something definitively.

^

It means to find, or to set, or to decide on the limits of something. So, think of it as excluding or removing all other options or possibilities.