x-y=500(1-15%)-(1-10%)y=950
10/x+y+3/x-y=-5 15/x+y-2/x-y=-1(用换元法解此方程组)
方程组x-y=500① x+15%-(y-10%y)=950②
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
若|x+2y-1|+y²+4y+4=0,求(2x-y)²-2(2x-y)(x+2y)+(x+2y)&
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
解方程组:(0.2x+0.1y)/2- (4x-y)/10=(x-y)/5+ (3x+0.5y)/30 (3x+2y-1
化简求值:【(x+Y)(X-Y)-(X-Y)的平方+2Y(2-Y)】除4Y,其中X=1 Y=2
x-y=500 (1+百分之15)x-(1-百分之10)y=950 方程组的解
解方程组(1)2x-3y=10,-4x+y=5 (2)3x-2y=15,5x-4y=23
用换元法解方程组:﹛(x+y)分之10+(x-y)分之3=-5 ﹛(x+y) 分之15 -(x-y) 分之2=-1
先化简,再求值 (1)[(x-y)的平方+(x+y)(x-y)]÷2x 其中X=2010,y=2009 (2)y(x+y
若|x+y-1|+(x-y-2)²=0,求代数式(x+2y)(x-2y)-(2x-y)(-y-2x)的值.