PREP+FF数学，裸奔在即，盼望NN救命！

第9题仔细一点算就可以算出来了

问题应该在第3个式子上吧，我把第三个写出来

premise: insist throughout   a#b=a+b-ab

  then      (a#b)#c=(a+b-ab)#c=()+c-()c=a+b-ab+c-ac-bc+abc

               a#(b#c)=a#(b+c-bc)=a+()-a()=a+b+c-bc-ab-ac+abc

        obvirously,  (a#b)#c= a#(b#c)

+2道题目~

A certain city with a population of 132000 is to be divided into 11 voting districts, and no district is to have a population that is more than 10 percent greater than the population of any other district, what is the minimum possible population that the least populated district could have?

答案是11000.求解过程！

6  +  X   Y    Z
   4  1   -5     m
   e  7    n    10
   f   2    -4     5
m+n=?

答案是5