4x y=15,3y-4x=负3,由1得4x=(3)将(3)代入2中得-搜答案-搜搜考试网

x^+2xy+y^+4=16(x+y)²=16-4=12(1)x^-2xy+y^=16(x-y)²=16(2)(1)-(2)2y*2x=-4xy=-1(3xy+6y^)+|x^-(

因为x-y=4xy所以x-2xy-y=2xy2x+3xy-2y=11xyx-2xy-y分之2x+3xy-2y=5.5

(-3x^y+2xy)-(4x^+xy)=-3x^y+2xy-4x^-xy=-3x^y+xy-4x^所以填上-3x^y+xy-4x^

x+y=5xy=-3(2x-3y-2xy)-(x-4y+xy)=2x-3y-2xy-x+4y-xy=x+y-3xy=5-3×(-3)=5+9=14

x+（xy-4x）-3y=x-4x-3y+xy=-3(x+y)+xy=1-3=-2

sqrt(x)+sqrt(y)-4x+y+4+1/4=0=sqrt(x-2)+sqrt(y+1/2)即sqrt(x-2)=0;sqrt(y+1/2)=0即x=2;y=-1/2y^(-x+3xy)=(-

=3x平方y-2x平方y+6xy-3x平方y+xy=-2x平方y+7xy=-2*1*(-2)+7*(-1)*(-2)=4+14=18

（2x-3y-2xy）-（x-4y+xy）=2x-3y-2xy-x+4y-xy=（2-1)x+(-3+4)y+(-2-1)xy=x+y-3xy因为x+y=5,xy=-3所以原式=5+9=14

（4xy+12y)+[7x-(3xy+4y-x)]=4xy+12y+7x-3xy-4y+x=xy+8x+8y=xy+8(x+y)=(-2)+8*3=-2+24=22

(1)×7+(2)×328y+27y=55xy所以y=0或x=1分别代入所以x=0.y=0x=1,y=1/2

(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)=-2xy+2x+3y-3xy-2y+2x-x-4y-xy=-6xy+3x-3y=-6xy+3*(x-y)当时,原式=-6*1+3*

x的平方+y的平方-4x+y+4分之17=0x的平方-4x+4+y的平方+y+4分之1=0(x-2)²+(y+2分之1)²=0则x=2,y=-2分之1y的负2次方+3xy=(-2分

由A=5x*2y-3xy*2+4xy,B=7xy*2-2xy+x*2y得,A+B=6x*2y+4xy*2+2xy则,所求的式子可转化为-0.5x(6x*2y+4xy*2+2xy)-5x*2y-3xy*

x+y=3xyx^4+y^4+2(xy)^2=9(xy)^2x^4+y^4=7x^2y^2xy的负二次方+x的负二次方y=x^2/y^2+y^2/x^2=x^4+y^4/x^2y^2=7

∵x-y=4xy，∴2x+3xy-2yx-2xy-y=2(x-y)+3xyx-y-2xy=8xy+3xy4xy-2xy=112．故答案为：112．

4xy－（2x²＋5xy－y²）＋2（x²＋3xy）=4xy－2x²-5xy+y²＋2x²＋6xy=5xy+y²x=-2,y=1/

=xy(1-2y^2)=-0.119616

x+x^-1=4两边平方x²+2+x-=6x²+x-²=14所以原式=2*14=28x+y=2xy=-3则x²+y²=(x+y)²-2xy=

1、x²+xy=5xy+y²=-4相减x²-y²=92、相加x²+2xy+y²=(x+y)²=1x²-y²=(

x-2y=15两边平方x^2-4xy+4y^2=225x^2+4y^2=225+4xy=225+4*(-25)=125所以x^2+4y^2-1=125-1=124