x2-5x+3+4xy-y2

x2-4y2-3xy+y+x（x-4y+1)(x+y)

x2－(a＋b)xy+aby2x2+4xy－5y2x2－5x+32x2+xy－y2－4x+5y－6（x+ay+ax^2+3x+2)(x+by+by^2+2y-3)

计算(x+y/x-y+4xy/y2-x2)(x2-9y2)/（x2+2xy-3y2）(x+y/x-y+4xy/y2-x2)(x2-9y2)/（x2+2xy-3y2）=[(x+y/x-y-4xy/(x+y)(x-y)](x+3y)(x-3y)

4x2-3y2+2xy-4x2+5x24x2-3y2+2xy-4x2+5x2=5x²+2xy-3y²=(5x-3y)(x+y)

(3/2x2-5xy+y3)-【-3xy+2(1/4x2-xy)+2/3y2】,其中/x-1/+(y+2)2=0原式=3/2x²-1/2x²-5xy+3xy+2xy+y³-2/3y²=x²+

因式分解：3x2+5xy-2y2+x+9y-4x2+x-(a2-a)3x2+4xy-y2x,y,a后面的2表示平方3x^2+5xy-2y^2+x+9y-4=(x+2y)(3x-y)+x+9y-4=(x+2y)(3x-y)+4(x+2y)-(

已知:x2+y2=7,xy=-2.求7x2-3xy-2y2-11xy-5x2+4y2已知:x2+y2=7,xy=-2.求7x2-3xy-2y2-11xy-5x2+4y27x2-3xy-2y2-11xy-5x2+4y2=2x²-14

已知x2-xy=5,xy-y2=-3,求代数式x2-y2和x2-2xy+y2的值.这样.那个x2是x的平方的意思,2xy是2乘xy的意思,因为键盘有限,打不出来,谢谢.x2-y2=x2-xy+xy-y2=5-3=2x2-2xy+y2=x2-

(x2+xy+y2)-4xy(x2+y2)想疯了!乱做后得出2(x+y)(1-4xy)+xy只要2分,不必理睬

因式分解2x2+xy-y2-4x+5y-6x2-y2+a2-b2+2ax+2by3x2+5xy-2y2+x+9y-4b4-2b2-82x2+xy-y2-4x+5y-6x2-y2+a2-b2+2ax+2by3x2+5xy-2y2+x+9y-4

已知x2+y2+4x-2y+5=0,求x2+2xy+y2值x²+y²+4x-2y+5=0x²+4x+4+y²-2y+1=0(x+2)²+(y-1)²=0因为(x+2)²和

-（x2-2xy-y2)+(5x2-2xy-3y2)-（x2-2xy-y2)+(5x2-2xy-3y2)化简-(x²-2xy-y²)+(5x²-2xy-3y²)=-x²+2xy+y²

4x2+4xy-3y2-8x+3因式分解=(2x+3y)(2x-y)-8x+3=(2x+3y-1)(2x-y-3)

2x2+xy-y2-4x+5y-6因式分解2x^2+xy-y^2-4x+5y-6=（x+y）(2x-y)-4x+5y-6=（x+y）(2x-y)+2(x+y)-6x+3y-6=(x+y)(2x-y+2)-3(2x-y+2)=(2x-y+2)

2x2+xy-3y2+x+4y-1因式分解2x²＋xy-3y²＋x＋4y-1=2×x×x＋x×y-3×y×y＋x＋4×y-1=x×2x＋x×y-y×3y＋x×1＋y×4-1=x×（2x＋y＋1）-y×（3y＋4）-1

因式分解x2-4y2-3xy+y+x分解为（x+y）(x-4y)+x+y=（x+y）(x-4y+1)

解方程组｛3x2-y2=8{4x2+12xy+9y2=1{x2+2xy+y2-4=0x2+xy+y2=44x2-9y2=0x2-2xy+y2-1=0还有{x2+y2=4xy-y2+4=0x2-----x的平方y2------y的平方还有{2

x+y=3,xy=-5,x2+y2=19,x2-xy+y2=24,求x-yx²+y²=19,x²-2xy+y²=29即（x-y）²=29∴x-y=±根号29全部展开收起全部展开收起

4x2-y2/x2-2xy+y2+(2x-y)/2x2-2xy57587857

已知x/y=3/5,求(x2-xy+2y2)/(x2+2xy-y2)的值设x=3k,则y=5k∴(x2-xy+2y2)/(x2+2xy-y2)=（9k²-15k²+50k²）/(9k²+30k