又遇到麻烦了

麦兜woo

A rectangular photograph is surrounded by a border that is 1 inch wide on each side.  The total area of the photograph and the border is M square inches.  If the border had been 2 inches wide on each side, the total area would have been (M + 52) square inches.  What is the perimeter of the photograph, in inches?



A. 34

B. 36

C. 38

D. 40

E. 42
题目都没太明白啥意思？border？

chenqinyang

就是外面有一圈框~~：）

巨型水母

设 长宽分别为ab (a+2)(b+2)=M
                          (a+4)(b+4)=M+52

上下两个等式相减 2(a+b)=40  所以D

linsonyeo

楼上正解， 不过这里没有指明rectangular是否是Square. 我们就可以假设它是Square. 这样更容易求解。
已知  M+52=(根号M＋2)^2
求4×（根号M－2）。

麦兜woo

明白了，谢谢~