一道化简数学题=[1/3*X+2/5*(115-X)]*10+[2/3*X+(115-X)*3/5]*5

中括号去掉得到:原式=（10/3x+460-4x)+(10/3x+230-3x)
=10/3x(460-4x+230-3x)
=10/3x(690-7x)
[1/3*X+2/5*(115-X)]*10+[2/3*X+(115-X)*3/5]*5
=(1/3*X)*10+(2/3*X)*5+(115-X)(20/5+15/5)
=20x/3-7x+805
=-x/3+805