How to determine if opening preflop with some hand for example 77542 from BTN is +EV or not?

Assuming it's five- or six-handed, it's best to run a Monte Carlo simulation with software including opponent modelling ( esp. for the blinds; not so important for the ranges of the players that have already folded ). If the BB ( or SB ) is fairly aggressive ( reraises with AA, some draws that include an ace and sometimes KK such as KKA ), this hand is normally a fold predraw since there is no ace kicker. With 77AKX ( X>=8 ), you normally open raise from the button since it's less likely any of the blinds have either KK, AA or any draw with an ace.

---"bigpooch"

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