设2x−yx+y=3,其中x,y≠0,则(2x−3y)3−(3x−2y)3(4x+2y)3−(x−7y)3=( )
设2x−yx+y=3,其中x,y≠0,则(2x−3y)3−(3x−2y)3(4x+2y)3−(x−7y)3=( )
若|x-y+3|与|x+y-1999|互为相反数,求x+2yx−y
已知3x-5y=0,则分式x−2yx+3y
若丨x-y+3丨与丨x+y-1995丨互为相反数,则x+2yx−y
若|x-y+3|与|x+y-1999|互为相反数,求x+yx−y
设实数x,y满足条件x≥0x≤yx+2y≤3
已知实数x、y满足|2x-y+1|+2(3x-2y+4)2=0,求代数式1−x−yx−2y÷x
设全集U={(x,y)|x,y∈R},集合M={(x,y)|y−3x−2=1},N={(x,y)|y≠x+1},则∁U(
已知x-3y=0,求2x+yx
设变量x,y满足约束条件x+y≥3x−y≥−1,则目标函数z=y+2x的最小值为( )
6x^2y+2xy-3x^2y^2-7x-5yx-4y^2x^2-6x^2y,其中|x+3|+(y-2)^2=0
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