X-2(Y+2)=3 3(2X-5)-8(3Y+2)=-1
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
10/x+y+3/x-y=-5 15/x+y-2/x-y=-1(用换元法解此方程组)
2(x-y)+3(x+y)2-5(x-y)-8(x+y)2-(x-y)
若3x-5y=0,则x+y/x=(),x-y/y=(),2x-3y/2x+3y=( )
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
先化简再求值(x-y)(x-2y)-1/2(2x-3y)(x+2y),其中x=2,y=2/5
(5x-y)(y+5x)-(3y+2x)(3y-2x) x=1 y=2
解方程组:(0.2x+0.1y)/2- (4x-y)/10=(x-y)/5+ (3x+0.5y)/30 (3x+2y-1
先化简,再求值:[(X+2Y)平方-(X+Y)(3X-Y)-5Y平方]除以(2X)其中X=-2,Y=1/2
(1)已知x+y=6,x²-y²=5,求x-y的值(2)若x+y=3,x²+y²
1.((y+2x)(-2x+y)+4(x+2y)^2)/3y 2.(2(x-y)^3-8(x-y)^2(x+y)+6y(
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)