{2100x+700y=(2100+700)*3% {900x+2700y=(900+2700)*5%
若3x-5y=0,则x+y/x=(),x-y/y=(),2x-3y/2x+3y=( )
(x+y/4)+(x-y/5)=3
10/x+y+3/x-y=-5 15/x+y-2/x-y=-1(用换元法解此方程组)
x+y=3,x²+y²=5,求(x-y)^2014
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
分式的加减:[(x/y-y/x)除以(x+y)+x(1/y-1/x)]除以1+x/y,其中x=5,y=2
(5x-y)(y+5x)-(3y+2x)(3y-2x) x=1 y=2
先化简在求值 (x+5y)(x+4y)-(x-y)(x+y),其中,x=-2又2/3,y=3/7
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
先化简再求值(x-y)(x-2y)-1/2(2x-3y)(x+2y),其中x=2,y=2/5
先化简再求值 :[(x+2y)²-(x+y)(3x-y)-5y²]÷(2x),其中x=—2,y=5
已知x=2,y=3,求代数式(x-y)*(x-y)^3*(x-y)^5*……*(x-y)^11