(x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5)
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/22 01:25:08
(x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5)
(x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5)
∵(x-y)/(x+y)=3,
∴可设 x-y=3a.(1) (a≠0)
x+y=a.(2)
(1)+(2)得 2x=4a,故x=2a; (2)-(1)得 2y=-2a, 故y=-a,
于是 (3x-2y-1)/(x+y-5)=(3a+2a-1)/(2a-a-5)=(5a-1)/(a-5)
当a=1时,原式=(5-1)/(1-5)=-1
因为a是x-y与x+y的公因数,其值不定,原式的值也就不可能确定.
∵(x-y)/(x+y)=3,
∴可设 x-y=3a.(1) (a≠0)
x+y=a.(2)
(1)+(2)得 2x=4a,故x=2a; (2)-(1)得 2y=-2a, 故y=-a,
于是 (3x-2y-1)/(x+y-5)=(3a+2a-1)/(2a-a-5)=(5a-1)/(a-5)
当a=1时,原式=(5-1)/(1-5)=-1
因为a是x-y与x+y的公因数,其值不定,原式的值也就不可能确定.
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
1奥数题x-2y/x+2y=3,求x-2y/3(x+2y)-3(x-2y)/x-2y的差
若x-y/x+y=5,求x-y/2x+2y+5x+5y/3x-3y的值
|x|=3 |y|=5 |x-y|=|x|+|y| 求 X+Y和 X-Y 等于多少
x>1,y>0,且满足xy=x^y,x/y=x^3y,求x+y
(1)已知x+y=6,x²-y²=5,求x-y的值(2)若x+y=3,x²+y²
(3x-y)^2+(3x+y)(3x-y),x=1,y=-2