矩形的周长是16cm,它的两边x,y是整数,且满足x^2-2xy+y^2-x+y-2=0,求矩形的面积.鄙视今生人逍遥...鄙视今生人逍遥...鄙视今生人逍遥...鄙视今生人逍遥...鄙视今生人逍遥...鄙
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/25 16:04:29
![矩形的周长是16cm,它的两边x,y是整数,且满足x^2-2xy+y^2-x+y-2=0,求矩形的面积.鄙视今生人逍遥...鄙视今生人逍遥...鄙视今生人逍遥...鄙视今生人逍遥...鄙视今生人逍遥...鄙](/uploads/image/z/4341512-56-2.jpg?t=%E7%9F%A9%E5%BD%A2%E7%9A%84%E5%91%A8%E9%95%BF%E6%98%AF16cm%2C%E5%AE%83%E7%9A%84%E4%B8%A4%E8%BE%B9x%2Cy%E6%98%AF%E6%95%B4%E6%95%B0%2C%E4%B8%94%E6%BB%A1%E8%B6%B3x%5E2-2xy%2By%5E2-x%2By-2%3D0%2C%E6%B1%82%E7%9F%A9%E5%BD%A2%E7%9A%84%E9%9D%A2%E7%A7%AF.%E9%84%99%E8%A7%86%E4%BB%8A%E7%94%9F%E4%BA%BA%E9%80%8D%E9%81%A5%EF%BC%8E%EF%BC%8E%EF%BC%8E%E9%84%99%E8%A7%86%E4%BB%8A%E7%94%9F%E4%BA%BA%E9%80%8D%E9%81%A5%EF%BC%8E%EF%BC%8E%EF%BC%8E%E9%84%99%E8%A7%86%E4%BB%8A%E7%94%9F%E4%BA%BA%E9%80%8D%E9%81%A5%EF%BC%8E%EF%BC%8E%EF%BC%8E%E9%84%99%E8%A7%86%E4%BB%8A%E7%94%9F%E4%BA%BA%E9%80%8D%E9%81%A5%EF%BC%8E%EF%BC%8E%EF%BC%8E%E9%84%99%E8%A7%86%E4%BB%8A%E7%94%9F%E4%BA%BA%E9%80%8D%E9%81%A5%EF%BC%8E%EF%BC%8E%EF%BC%8E%E9%84%99)
矩形的周长是16cm,它的两边x,y是整数,且满足x^2-2xy+y^2-x+y-2=0,求矩形的面积.鄙视今生人逍遥...鄙视今生人逍遥...鄙视今生人逍遥...鄙视今生人逍遥...鄙视今生人逍遥...鄙
矩形的周长是16cm,它的两边x,y是整数,且满足x^2-2xy+y^2-x+y-2=0,求矩形的面积.
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矩形的周长是16cm,它的两边x,y是整数,且满足x^2-2xy+y^2-x+y-2=0,求矩形的面积.鄙视今生人逍遥...鄙视今生人逍遥...鄙视今生人逍遥...鄙视今生人逍遥...鄙视今生人逍遥...鄙
x^2-2xy+y^2-x+y-2=(x-y)^2-(x-y)-2=0 设x-y=a 则a^2-a-2=0 解得a=2或-1 若a=2 则x=9 y=7 面积为63 若a=-1 x=7.5 y=8.5(舍去) 所以面积为63
X²-2XY-Y²-(X-Y)-2=0
(X-Y)²-(X-Y)-2=0
(X-Y+1)(X-Y-2)=0
X-Y+1=0,X=Y-1;
或X-Y-2=0,X=Y+2
因为周长=2(X+Y)=16,X+Y=8
X、Y为两整数,当差为1时,显然一奇一偶,和不可能为8
因此X+Y=8,X=Y+2
X=5,Y=3
矩形面积为15平方厘米
fsdfsad
楼下的是不是数学教师,太厉害了
一楼答案
x^2-2xy+y^2-x+y-2=(x-y)^2-(x-y)-2=0 设x-y=a 则a^2-a-2=0 解得a=2或-1 若a=2 则x=9 y=7 面积为63 若a=-1 x=7.5 y=8.5(舍去) 所以面积为63
这是楼上的,我来纠正
x^2-2xy+y^2-x+y-2=(x-y)^2-(x-y)-2=0 设x-y=a 则a^2-a-2=0 解得a...
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一楼答案
x^2-2xy+y^2-x+y-2=(x-y)^2-(x-y)-2=0 设x-y=a 则a^2-a-2=0 解得a=2或-1 若a=2 则x=9 y=7 面积为63 若a=-1 x=7.5 y=8.5(舍去) 所以面积为63
这是楼上的,我来纠正
x^2-2xy+y^2-x+y-2=(x-y)^2-(x-y)-2=0 设x-y=a 则a^2-a-2=0 解得a=2或-1 若a=2则x-y=2 ①
又2(x+y)=16则x+y=8 ②
联立①②得x=5,y=3则S=xy=15
若a=-1则则x-y=-1 ③联立②③得x=7/2,y=9/2则S=xy=63/4
因为没有规定xy哪个是长哪个是宽,所以一个都不能舍去
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