(xy-x平方)(1 x 1 y-x)-搜答案-搜搜考试网

解2(x²-xy)-3(2x²-3xy)=(2x²-6x²)+(-2xy+9xy)=-4x²+7xy再问：��|-15|-8�£�-2��+4*�

(3x的平方+2xy-2分之1x)-(2x的平方-xy+x)=3x+2xy-x/2-2x+xy-x=x+3xy-3x/2

xy(xy+1)+(xy+3)-2(x+y+1/2)-(x+y-1)^2=xy(xy+1)+(xy+1)+2-2(x+y)-1-[(x+y)^2-2(x+y)+1]=(xy+1)^2+2-2(x+y)

=-x-(2y-2+3x)+2(x+4)=-x-2y+2-3x+2x+8=-4x-2y+10

1、原式=[2x/(x^2-1)]-[(x+1)/(x^2-1)]=[2x-(x+1)]/(x^2-1)=(x-1)/(x^2-1)=(x-1)/[(x+1)(x-1)]=1/(x+1)2、原式=[x

（3x²+2xy-1/2x）-（2x²-xy+x）=3x²+2xy-1/2x-2x²+xy-x=x²+3xy-3/2x

楼主是不是把题写错了呀,应该是（X+2)^2+/Y+1/=0吧因为（X+2)^2大于等于0/Y+1/大于等于0所以只有同时为0时,和才为0即X=-2Y=-1带入原式=4

(8xy-3x平方)-5xy-2(3xy-2x平方)=8xy-3x²-5xy-6xy+4x²=x²-3xy=4+6=10

xy+x/x的平方+2x+1=x(y+1)/(x+1)^2不能继续约分了题目如果是xy+y/x的平方+2x+1=y(x+1)/(x+1)^2=y/(x+1)

2x²-3xy+(2xy-x²)=2x²-3xy+2xy-x²=x²-xy=x(x-y)

3x²y+{xy-[3x²y-(4xy²+1/2xy)]-(4x²y+3/2xy)}=3x²y+xy-3x²y+4xy²+1/2x

原式(-xy/3)²*[xy(2x-y)-2x(xy-y²)]=(x²y²/9)(2x²y-xy²-2x²y+2xy²)

5xy平方-2x平方y+[3xy平方-(4xy-2x平方y-2x平方y)]＝5xy平方-2x平方y+[3xy平方-4xy＋2x平方y＋2x平方y)]＝5xy平方-2x平方y+3xy平方-4xy＋2x平

=x^3-y^3-(x^3+y^3)=-2y^3^3表示三次方

[3xy(1-x)-6xy(x-1/2)]*2x*(-xy)平方=(3xy-3x²y-6x²y+3xy)(2x³y²)=12x^4y³-18x^5y&

(3x²+2xy-x/2)-(2x²-xy+x)=x²+3xy-3x/2

x｛x-1｝-｛x＾2-y｝＝-3即x^2-x-x^2+y=-3-x+y=-3x-y=3而x＾2+y＾2-2xy=(x-y)^2=3^2=9

X²-XY-6Y²+2X-Y+1=(X+1)²-Y(X+1)-6Y²=(X+1-3Y)(X+1+2Y)再问：学生不才老师您第一步我就不知道怎么得到的再答：X2-

2和3再问：要完整过程！！！~~再答：=。=∵x平方-2xy+y平方=1∴（x-y）平方=1∴x-y=1或x-y=-1。再代入第一个方程里面。算呗

5x²+5xy+y²+2x+1=04x²+y²+4xy+2x+x²+1=0（2x+y）²+（x+1）²=0得{2x+y=0---①