分别设为x,y,z!列方程：x+y+z=100 (1)10x+3y+0.5z=100(2)(2)*2-(1)得10x+5y=100!然后用待定系数法!解得答案!x课取9,8,7,6,5,4,3,2,1相应y可取2,4,6,8,10,12,14,16,18z可取89,88,87,86,85,84,83,82,81就是这样!...