[求助]

more96

princeton 上有一题没看懂：
A tailor trims 4 feet from opposite edges of a square piece of cloth, and 5 feet from the other two edges. If 120 square feet of cloth remain, what was the length of a side of the original piece of cloth?
The anwer is 20.

sherry

就是正方形切成长方形，一组对边各切4，另一组对边各切5，剩下 (x-8).(x-10)=120，所以 x=20