Equities: Justified PE, P/B, P/S, dvd yield understand, logic, these

Walex

Can anyone explain what is going on with the "justifying" of the multiples?

PE: [(1 - b) x (1 + g)]/(r - g)

P/B: (ROE - g)/(r - g)

P/S: [(E/S) x (1 - b) x (1 + g)]/(r - g)

Dividend Yield: (r - g)/(1 + g)

I don't understand the logic of these formulas