yogi_Multiple Criteria Match In Two Sheets Within A Spreadsheet (WorkBook)

Google Spreadsheet   Post  #2392

Yogi Anand, D.Eng, P.E.      ANAND Enterprises LLC -- Rochester Hills MI     Mar-11-2018

question by: Rob N.
https://productforums.google.com/forum/?utm_medium=email&utm_source=footer#!topic/docs/CUD_tKZ1uFg;context-place=forum/docs
Help with an "If formula" with multiple conditions

I have account numbers that are likely to appear in two distinct columns with the same header ("Accounts") located in two separate tabs ("Main" & "Stock"). 

I need help with a formula that would return a specific text ("System") only IF the following conditions are met;

1. Two account numbers under columns B (in separate tabs) are matching; 

2. The adjacent cell ("Main" tab, Column C-"Activity) to the matching account number must contain one of these values: "Repo WL" or "Sold".

A link to the sample data : https://docs.google.com/spreadsheets/d/1KQfCQypF56cAOBtRwyMoefqrzOKwUrOnQt3twyKXlpI/edit?usp=sharing

Thank you for your help.