A=｛(x,y)|2x+3y=12,x∈N,y∈N｝.B=｛x|14/(3-x)∈Z,x∈Z｝试用列举法表示集合A.B

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 12y(x-y)^2-8(x-y)^3=? 若[-3(x+y)^m*(x-y)^2n]^2*[-(x+y)^2]=-a(x+y)^10*(x-y)^12-n,求m,n的值 3x+y=2 -y/x+y=123x+y=2 （-y/x）+y=12 假设集合U={(x,y)|x∈R,y∈R },A={(x,y)|2x-y+m>0},B={(x,y)|x+y-n (x+y)(x-y)+(x-y)平方-(x-y)(3x-y) 其中x=-2 y=3分之一 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 设集合A=｛y/y=x²-2x+3,x∈R｝,B=｛y/y=-x²+2x+10,x∈R｝,求A∩B设集合A=｛（x,y)/y=x+1,x∈R｝,B=｛（x,y)/y=-x²+2x+3/4,x∈R｝,求A∩B 已知方程组 2x+y=3a x-2y=a 求x/y (x+y)(2x-3y)=? A={(x,y)|y=-x^2+mx-1},B={(x,y)|y=3-x,0A={(x,y)|y=-x^2+mx-1},B={(x,y)|y=3-x,0 已知3x+2y=a,2x+3y=b,则(x+y)(x-y)=? 集合A={（x,y)|y=-x^2+mx-1},B={(x,y)|y=3-x,0 方程组:3（x+y)-a(x-y)=16,2(x+y)+b(x-y)=15的解是什么? 如果方程组x-y=a-3,2x+y=5的解x、y满足x>0,y 解关于x、y的方程组2x-y=a,2x+y=-3