X Y=3,X-2Y=3 A
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由|x-2a|+(y+3)²=0可得x=2a,y=-3带入A,B可得A=8a²+16a+3,B=16a²+30a+21带入-2A+B=a得a=5,A=283
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(
由|x-2a|+(y+3)²=0得:x=2a,y=-3,B-A=(4x²-6xy+2y²+3x-y)-2(2x²-3xy+y²-x+2y)=5X-5Y
(-3x^y+2xy)-(4x^+xy)=-3x^y+2xy-4x^-xy=-3x^y+xy-4x^所以填上-3x^y+xy-4x^
是不是-2A+B=2a所以-4x²+6xy-2y²+2x-4y+4x²-6xy+2y²+3x-y=5x-5y=5a+15=2aa=-3A=18-27+9+3-6
xy=-a2+a+2=(2-a)(a+1)=[-(2-a)][-(a+1)]则x=2-ay=a+1x+y=3或者x=-(2-a)y=-(a+1)x+y=-3又因为x+y=3所以x=2-ay=a+1
2(x+xy)-[(xy-3y)-x]-(-xy)=2x+2xy-xy+3y+x+xy=3x+3y+2xy=3(x+y)+2xy=3*(-2)+2*3=0
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
设A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²-3x-y,且B-2A=a所以a=B-2A=4x²-6xy+2y²-3x-y
1、x-y=a+32x+y=5a二式相加得3x=6a+3,得x=2a+1代入得y=a-2所以方程组解为x=2a+1,y=a-22、2a+1>a-2,解得a>-3a-2>0,解得a>2综上可得a>23、
∵x-y=4xy,∴2x+3xy-2yx-2xy-y=2(x-y)+3xyx-y-2xy=8xy+3xy4xy-2xy=112.故答案为:112.
∵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
因为,│x-2a│+(y+3)²=0由非负性可得,x-2a=0且y+3=0解得,x=2a,y=-3又,B-2A=-x-5y=a所以,2(x+5y)+x=0即,3x+10y=0将y=-3代入,
1根据题意得x=2ay=-3B-2A=a4X^2-6XY+2Y^2-3X-Y-4X^2+6XY-2Y^2+2X-4Y=a整理得-X-5Y=a带入得a=5A=102根据题意得a=2/3b=-3/2c=1
∣x-2a∣+(y+3)²=0因为∣x-2a∣≥0,(y+3)²≥0所以∣x-2a∣=0,(y+3)²=0所以x=2a,y=-3B-2A=(4x²-6xy+2y
x=2ay=-3A=2x^2+9x+9-x-6=2x^2+8x+3B=4x^2+18x+18-3x+3=4x^2+15x+21B-2A=-x+15=a又x=2a所以x=10A=283
y=-3,x=2aB-2A=5x-5y=a10a+15=aa=-5/3x=-10/3将x、y代入A得到答案
A=y+2xy记得采纳啊