are free cash flow and FCFF the same? wiki tells me they are the same. but qbank tells me FCF=NI+NCC-Capex. can someone explain please ?

Yes, they are synonymous - however, you will encounter some variants outside of the CFAI curriculum. Stick to this for the exam: FCF = NI + NCC + [int exp * (1 - t)] - CapEx - WCapInv