(a-2)x y=b (b 1)x-2y=a 3有无数解
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A-2B=2x²+3xy+2y-1-2(x²-xy+x-1/2)=2x²+3xy+2y-1-2x²+2xy-2x+1=5xy-2x+2y=x(5y-2)+2y根
(1)A-B=2x^2-3xy+2y^2-(x^2+xy-3y^2)=2x^2-3xy+2y^2-x^2-xy+3y^2=x^2-4xy+5y^2(2)2A-3B+C=0即:2(2x^2-3xy+2y
A-2B=5x²-3xy²+2xy-2(7xy²-2xy+x²y)=5x²-3xy²+2xy-14xy²+4xy-2x²
1.=3(a-b)/(10ab)*(25a^2b^3)/((a+b)(a-b))=15/2*(ab^2)/(a+b)2.=(x+2y)(x-2y)/(x+y)^2*2x(x+y)/(x+2y)=2x(
x^2-3xy+4y^2=(x^2+xy)+4(y^2-xy)=a+4
解2A-[B-(B-A)+2A+B]=2A-[B-B+A+2A+B]=2A-(B+3A)=-B-A=-(x²+2xy+y²-3)-(x²-2xy+y)=-x²-
原式既为Bx-xy-AB+Ay=x^2-9xy+8y^2,则A=xB=8y
∵A=4x²-4xy+y²B=x²+xy-5y²∴(3A-2B)-(2A+B)=3A-2B-2A-B=A-3B=4x²-4xy+y²-3(x
3A+6B=3(2x²+3xy-2x-1)+6(-x²+xy-1)=6x²+8xy-6x-3-6x²+6xy-6=((14y-6)x-9值与x无关则x系数为0所
(1)x=y=-2时,A=2×(-2)^3+3×(-2)×(-2)+2×(-2)-1=-9,B=(-2)^2-(-2)×(-2)+(-2)-1/2=-5/2A-2B=-9+5=-4(2)A-2B=2x
已知A=4x²-4xy+y²,B=x²+xy-5y²则,A-3B=4x^2-4xy+y^2-3(x^2+xy-5y^2)=4x^2-4xy+y^2-3x^2-3
a-2b=(5x²y-3xy²+4xy)-2(7xy²-2xy+x²y)=5x²y-3xy²+4xy-14xy²+4xy-2x
A+B=(x²-3xy+y²)+(2x²+xy-9y²)=x²-3xy+y²+2x²+xy-9y²=3x²-2
A=y的平方+xy—x的平方,B=y的平方-xy+2x的平方,所以A-B=y的平方+xy—x的平方-y的平方+xy-2x的平方=2xy-3x的平方,3A+2B=3y的平方+3xy—3x的平方+2y的平
B1=B(A2-A1)-B2(A-A1)+A2-A
4x²+8xy+9y²=2x²+2x²+xy+xy+6xy+9y²=2a+9y²+6xy=2a+3y²+2xy+3y²+
∵A=8x²y-6xy²-3xy,B=7xy²-2xy+5x²y ∴C=3(A+B) =3(8x²y-6xy²-3xy+7xy²
已知A=5x^2y-3xy^2+4xy,B=7xy^2-2xy+x^2y.(1)求A-2B的值A-2B=5x^2y-3xy^2+4xy-2*(7xy^2-2xy+x^2y)=5x^2y-3xy^2+4
①:A=5x²y-3xy²+4xy=xy(5x-3y+4)B=7xy²-2xy+x²y=xy(7y-2+x)A-2B=xy(5x-3y+4)-2[xy(7y-2