Learn Romanian: Din moment ce avem rezultatul, mulți dintre ei au oferit feedback pozitiv. - Since we have the result, many of them offered positive feedback.

We use dintre (meaning 'out of' or 'among') because it is followed by the plural pronoun ei. In Romanian, you must use dintre instead of din before plural pronouns and articulated plural nouns to indicate a part out of a whole group.

Does din moment ce mean the same thing as de când?

Both can translate to 'since' in English, but they are used differently. Din moment ce means 'given that' or 'because' (causal). De când refers strictly to time (temporal). Here, the fact that we have the results is the logical reason they offered feedback.

The word feedback is from English. How do you know what gender it takes for the adjective pozitiv?

Recent English loanwords describing inanimate concepts are almost always adopted as neuter nouns in Romanian. Because it acts as a singular neuter noun here, it takes the singular masculine/neuter adjective pozitiv. If you needed the definite article 'the', you would add the neuter ending to make it feedbackul.

Could we just say mulți din ei in spoken Romanian?

You might hear native speakers say din instead of dintre in fast, casual speech, but it is considered grammatically incorrect. Standard Romanian requires dintre before a pronoun like ei to properly express the partitive.