Ich vermute, dass es so gemeint ist
log( (12:(a²-b²))^5 : (8:(a+b))^3 )
= log( (12:((a-b)*(a+b))^5 : (8:(a+b))^3 )
=5*log( (12:((a-b)*(a+b))) - 3*log(8:(a+b))
=5* ( log(12) - log((a-b)*(a+b)) - 3*( log(8) - log(a+b) )
=5* ( log(3*4) - ( log(a-b)+log(a+b)) - 3*(3* log(2) - log(a+b) )
=5* ( log(3)+2*log(2) - ( log(a-b)+log(a+b)) - 3*(3* log(2) - log(a+b) )
=5log(3)+10*log(2) - 5log(a-b)-5log(a+b) - 9log(2) + 3 log(a+b)
=5log(3)+log(2) - 5log(a-b)-2log(a+b)