here are the notes from my study log, hope t helps
If the CPI is expected to be the same for the remainder of the project, EAC can be calculated using: EAC = BAC/CPI
which basically means you expect the future of the project to be the same as the previous period.
If future work will be accomplished at the planned rate, use: EAC = AC + BAC – EV
which means whatever happened in the past period will not affect the plan of the remaining work.
If the initial plan is no longer valid, use: EAC = AC + Bottom-up ETC
which means the initial planning turned out invalid and the remaining work will be re-estimated.
If both the CPI and SPI influence the remaining work, use: EAC = AC + [(BAC – EV)/(CPI x SPI)]