已知 1/x - 1/y =3 则分式 (2x+3xy-2y)/(x-2xy-y)的值为多少?
来源:学生作业帮 编辑:拍题作业网作业帮 分类:数学作业 时间:2024/11/01 06:53:33
已知 1/x - 1/y =3 则分式 (2x+3xy-2y)/(x-2xy-y)的值为多少?
如果m为整数,那么,使分式(m+3)/(m+1)的值为整数的值有多少个?
A.2个 B.3个 C.4个 D.5个
如果m为整数,那么,使分式(m+3)/(m+1)的值为整数的值有多少个?
A.2个 B.3个 C.4个 D.5个
解法一:
1)因(1/x) - (1/y ) = 3,可得:(y-x)/xy=3,得:x+3xy-y=0.
2)2x+3xy-2y)/(x-2xy-y)可以进一步分解成:
{x+(x+3xy-y)-Y}/{(x+3xy-y)-5xy}
3)将x+3xy-y=0.代入{x+(x+3xy-y)-Y}/{(x+3xy-y)-5xy}中,
得:(x+0-y)/(0-5xy)=(x-y)/(-5xy),得:-(y-x)/(-5*xy)
同理将1)中的:(y-x)/xy=3 代入:-(y-x)/(-5*xy),
得:-3/(-5)=3/5.
因此(2x+3xy-2y)/(x-2xy-y)=3/5.
解法二:
1)将(2x+3xy-2y)/(x-2xy-y)上下分别都除以xy,得:(2/y+3-2/x)/(1/y-2-1/x)
2)得:(2/y-2/x+3)/(1/y-1/x-2)
因(1/x) - (1/y ) = 3,因此(1/y) - (1/x) = -3
因此得(-3*2+3)/(-3-2)=3/5.
m+3)/(m+1)=(m+1+2)/(m+1)=1+2/(m+1)是整数
则2/(m+1)是整数
所以m+1是2的约数
m+1=1,-1,2,-2
m=0,-2,1,-3
选C
1)因(1/x) - (1/y ) = 3,可得:(y-x)/xy=3,得:x+3xy-y=0.
2)2x+3xy-2y)/(x-2xy-y)可以进一步分解成:
{x+(x+3xy-y)-Y}/{(x+3xy-y)-5xy}
3)将x+3xy-y=0.代入{x+(x+3xy-y)-Y}/{(x+3xy-y)-5xy}中,
得:(x+0-y)/(0-5xy)=(x-y)/(-5xy),得:-(y-x)/(-5*xy)
同理将1)中的:(y-x)/xy=3 代入:-(y-x)/(-5*xy),
得:-3/(-5)=3/5.
因此(2x+3xy-2y)/(x-2xy-y)=3/5.
解法二:
1)将(2x+3xy-2y)/(x-2xy-y)上下分别都除以xy,得:(2/y+3-2/x)/(1/y-2-1/x)
2)得:(2/y-2/x+3)/(1/y-1/x-2)
因(1/x) - (1/y ) = 3,因此(1/y) - (1/x) = -3
因此得(-3*2+3)/(-3-2)=3/5.
m+3)/(m+1)=(m+1+2)/(m+1)=1+2/(m+1)是整数
则2/(m+1)是整数
所以m+1是2的约数
m+1=1,-1,2,-2
m=0,-2,1,-3
选C
已知1/x-1/y=2010,则分式(x+2xy-y)/(x-y)的值为多少?
已知1/x+1/y=3,求分式3x-2xy+3y/x+xy+y的值
已知,1/x+1/y=5.,求分式3x+xy+3y/x-2xy+y的值
已知x分之1-y分之1=3,则分式(x-2xy-y)分之(2x+3xy-2y)的值为?
已知1/x-1/y=3则分式(2x-3xy-2y)/(x-2xy-y)的值为
已知x/1-Y/1=3,则分式x-2xy-y/2x+3xy-2y的值为_
已知x分之1+y分之1=5,则分式x+2xy+y分之2x-3xy+2y的值为
已知x-y/xy=3,求分式2x+3xy-2y/x-2xy-y的值.
已知1/x减1/y=-3,则(2x+xy-2y)/x-xy-y的值为
分式y/2x,x/3y^2,1/xy的最简公分母为多少?
解一道分式题已知1/x-1/y=3 求分式(4x-5xy-4y)/(3x-2xy-3y)的值.
1/x+1/y=3.求分式3x-2xy+3y/x+xy+y的值