已知长方形的周长为16cm,它的一组邻边长分别为x,y,且x-y-x²+2xy-y²+2=0,x-y≠-1,求其面积
已知长方形的周长为16cm,它的一组邻边长分别为x,y,且x-y-x²+2xy-y²+2=0,x-y≠-1,求其面积
2*(x+y)=16 。。。。1
x-y-x²+2xy-y²+2=0
(x-y+1)(x-y-2)=0
因为x-y≠-1
所以x-y-2=0 .。。。2
连列1,2两个式子
解得
x=5
y=3
面积=xy=3*5=15
∵长方形的周长为16cm,它的一组邻边长分别为x,y
∴2(x+y)=16
且x-y-x²+2xy-y²+2=0,x-y≠-1,x-y-x²+2xy-y²+2=x-y-(x²-2xy+y²)+2=x-y-(x-y)²+2=0,
∴x-y=(x-y)²-2,另a=x-y,则a≠-1,a=a²-2,∴a=2,∴x-y=2
解方程组得x=5,y=3,面积S=xy=15
S=15CM^2
x-y-x²+2xy-y²+2=0
(x-y)-(x²-2xy+y²)+2=0
(x-y)²-(x-y)-2=0
(x-y-2)(x-y+1)=0
∵x-y≠-1
∴x-y=2
∵x+y=16÷2=8
解得x=5,y=3
∴面积=3×5=15㎝²
x-y-x²+2xy-y²+2=0
(x-y+1)(x-y-2)=0
又x-y≠-1
故x-y-2=0
即x-y=2
又x+y=8
解得
x=5
y=3
面积=xy=3*5=15
根据题意有x+y=16/2=8
x-y-x²+2xy-y²+2=0
-(x²-2xy+y²)+(x-y)+2=0
(x-y)²-(x-y)-2=0
(x-y-2)(x-y+1)=0
因为x-y≠-1,所以x-y=2,与x+y=8联立求解为
x=5、y=3
面积为5*3=15。
x-y-x²+2xy-y²+2=0
x-y-(x²-2xy+y²)+2=0
(x-y)(1-(x+y))+2=0
-7(x-y)=-2
x-y=2/7
x+y=8
xy=783/49