x y=a b,x^3 y^3=a^3 b^3-搜答案-神马作文网

AB是正比XY是反比

3xa+(10-y)b=2xb“+”(4y+4)a.（用“+”补上漏掉的符号）[3x-4y-4]a＋[10-y-2x]b＝0.a,b不共线：3x-4y-4=0.10-y-2x=0.解得,x=4.y=2

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(

(-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

4A+B-(A-B)=4A+B-A+B=3A+2B=3(x^2+xy+y^2)+2(x^2-xy+y^2)=3x^2+3xy+3y^2+2x^2-2xy+2y^2=5x^2+xy+5y^2=(x^2+

原式=4A+B-A+B=3A+2B=3x²+3xy+3y²+2x²-2xy+2y²=5x²+xy+5y²=(x²+3xy+4y&#

再问：-ab(a-b)²+a(b-a)²-ac(a-b)²再答：

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

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、

1a²-2ab-3b²=0(a+b)(a-3b)=0(1)若a=-b：b/a+a/b=(-1)+(-1)=-2(2)若a=3b：b/a+a/b=3+1/3==10/32x²

∵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

AB平行x轴.y=-3AB长度为5x=9或者-1xy=-27或者3

∣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+y=0ab=1所以1/2(x+y)+3ab=3

x+y=1,xy=3有问题,已不在实数范围内二分之一a²-0.5ab=a/2*[a-b]2009²-2008*2010=2009²-[2009-1]*[2009+1]=2