若x+y=4 xy=-2那么x^2+y^2等于() A 25 B 20 C 10
3a-3b/10ab*25a^b3/a^-b^= x^-4y^/x^+2xy+y^/x+2y/2x^+2xy
如果a=3x^2-xy+y^2,b=2x^2-3xy-2y^2,那么2a-3b等于多少?
如果A+3x²-xy+y²,B=2x²-3xy-2y²,那么2A-3B等于多少?
1.已知,x+y=-6,x-y=5 A.(x+y)²=-36 B.(y-x)²=-10 C.xy=2
由已知x+y=-2,xy=3那么2(x+xy)-[(xy-3y)-x]-(-xy)等于多少?
设A=2x-3xy+y+x-3y,B=4x-6xy+2y+4x-y,若|x-3a|+(y+3)=0,且B-2A=a.求A
A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y,若x=
设A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²-3x-y,若x
设A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y.若x
以知x^2-4xy+4y^2=0,那么分式(X+Y)/(X-Y)的值等于?
已知3x^2+xy-4y^2=0【x不等于y],那么x/y等于多少
如果1\x-1\y=2,那么3x+5xy-3y\x-xy-y等于多少