How do faction bonuses add up?

[kguittar]

I know I saw a simple math equation of how the faction bonuses, specifically health, add up. Can someone help me find that back? A search just yields tons of faction recruitment threads

[Corsair]

=trunc(1-(.95^x),2) where x is the number of faction upgrades, will give you your faction health reduction. Add in multipliers for any unit boosts to get your total. Ex: =trunc(1-(.95^x)*0.70,2) if you have the P-91 Pounder (30% reduction). Or just look in your total boost, that is accurate nowadays.