A parking lot measures 11m by 6m.The lot is enlarged by paving a uniform border alont 3 sides of the originial lot.Find
问题描述：
A parking lot measures 11m by 6m.The lot is enlarged by paving a uniform border alont 3 sides of the originial lot.Find the width of the newly paved border if the total area of the new lot is 120 metres squared.
请写出演算过程.
答
设三个方向同时扩展x米.有两种方案
第一：一条11m的边保持不动,则方程为（11+2x）（6+x）=120
第二：一条6m的边保持不动,则方程为（6+2x）（11+x）=120
两个方程都可以解出来.然后也就知道新的边界长度了.