设A=x²-xy,B=xy+y²,求:(1):A+B(2):3A-B
(1).设A=2X²-3Xy+y²+X-3y,B=4X²-6xy+2y²+4X-
已知A=x²-2xy+y,B=x²+2xy+y²-3,求2A-[B-(B-A)+2A+B]
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
(x-A)*(B-y)=x^2-9xy+8y^2,求A,B
已知2x²+xy=a,3y²+2xy=b,求4x²+8xy+9y²的值(用a,b
已知A=4x²-4xy+y²,B=x²+xy-5y²,求:⑴A-3B;⑵2A+B
已知:A=X*X-3xy+y*y,B=2x*x+xy-3y*3y.求A+B,A-B,A+2B
已知A=x²+3y²-5xy,B=2xy+2x²-y²,求:(1)3A-B (2
已知A=2x²+3xy-2x-1,B=-x²+xy-1,3A+6B的值与x无关,求y
设A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²-3x-y,若x
已知A=3x²y-xy²,B=xy-3x²y,且|x-1|+(y+3)²=0,求
因式分解2x²y-xy-3y (-a+b)+c²(a-b)