数学题 12-(9-y)=5(y-4)-7(7-y)

问题描述:

数学题 12-(9-y)=5(y-4)-7(7-y)

12-(9-y)=5(y-4)-7(7-y)
12-9+y=5y-20-49+7y
5y+7y-y=12-9+20+49
11y=72
y=72/11
y=11 分之72