问题
填空题
一个正方形一组对边减少3cm，另一组对边增加3cm，所得的长方形的面积与这个正方形的每边都减去1cm后所得的正方形的面积相等，则原来的正方形的边长为______．
答案
设原来的正方形的边长为xcm，根据题意得
（x-3）（x+3）=（x-1）2，
解得：x=5．
故答案为：5cm．
搜题请搜索小程序“爱下问搜题”
一个正方形一组对边减少3cm，另一组对边增加3cm，所得的长方形的面积与这个正方形的每边都减去1cm后所得的正方形的面积相等，则原来的正方形的边长为______．
设原来的正方形的边长为xcm，根据题意得
（x-3）（x+3）=（x-1）2，
解得：x=5．
故答案为：5cm．
| Questions refer to the following graph.
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If every student who was in the eleventh grade in 1996 and who used a computer in school at least once a week used a computer at least once a week in 1997, and if 20% of those students who were in the eleventh grade in 1996 and who did not use a computer in school at least once a week, did use a computer in school once a week in 1997, then what percent of twelfth-graders in 1997 used a computer in school at least once a week
A．(A) 40%
B．(B) 50%
C．(C) 60%
D．(D) 70%
E．(E) 80%
