若A*(7x-y)=y^2-49x^2若A*(7x-y)=y^2-49x^2 A等于多少

若A*(7x-y)=y^2-49x^2若A*(7x-y)=y^2-49x^2 A等于多少 若集合A={(x,y)|y>=|x-2|} ,B={(x,y)|y 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 若2x-y=a,x+2y=a,则x：y=? 若2x+y+a,x-2y=a,则x/y=? 若(x+y)(x-y)^2-xy(x+y)=A(x+y),则A=什么 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 若集合A={(x,y)|4x+y=6},B={(x,y)|3x+2y=7},则集合A∩B= 已知x属于R,y>0,集合A={x|x*x+x+1,-x,-x-1},集合B={-y,-y/2,y+1}若A=B,则x*x+y*y的值为 若f(x+y,y/x)=x^2-y^2,则F(X,Y)= 若x*x+y*y=x+y-1/2,求x,y的值如题 若2x=5y,则下列式子中错误的是() A x/y=5/2 B y/x=2/5 C x+y/x=7/5 D x-y/y=3/2 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 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 若x、y满足2x+y=6,x-3y=1,求7y(x-3y)²-2(3y-x)³的值 若x-y=2(x+y),求代数式x-y/x+y+x+y/x-y求代数式 x+y分之x-y+x-y分之x+y 已知:y=ax的3次方+bx+3,当x=-1/2时,y=-7,试求x=1/2时,y的值 若函数y=2/(x-2) (x∈A)的值域为{y|y