1-bx
m= --------------
1+bx
m*(1+bx)=1-bx
m+ mbx=1 -bx
mbx+bx=1-m
bx*(m+1)=1-m
1-m
bx= --------------
m+1
1-m
x= ---------------
b*(m+1)
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P=mnV²/3
3*P=mnV²
V=√(3P/mn)