x2-y2+2x+6y-8

已知X2+Y2+8X+6Y+25=0求代数式X2++XY+4Y2分之X2-4Y2减X+2Y分之X的值X2+Y2+8X+6Y+25=0x²+8x+16+y²+6y+9=0(x+4)²+(y+3)²=0∴

X2+Y2+8X+6Y+25=0求代数式(x2-4y2/x2+4xy+4y2)-x/x+2yX2+Y2+8X+6Y+25=0x^2+y^2+8x+6y+25=0x^2+8x+16+y^2+6y+9=0(X+4)^2+(y+3)^2=0x=-

x2-2xy+y2=4x2+y2-x-y=6解不等式x2-2xy+y2=4x2+y2-x-y=6解不等式x²-2xy+y²=4；所以(x-y)²=4x-y=±2,即x=y±21）假设x=y+2,则：由x

已知x2-y2=8,x-y=2,求x2+y2的值x=y+2代入得,Y=1,X=3.所以答案是10

若X2+Y2-2X-6Y+10=0,求（x2-y2)/xy的值10拆成1+9X2-2X+1+Y2-6Y+9=0(X-1)2+(Y-3)2=0平方大于等于0,相加等于0,若有一个大于0,则另一个小于0,不成立.所以两个都等于0所以X-1=0,

2/1(x2-y)+3/1(x-y2)+6/1(x2+y2)2/1(x²-y)+3/1(x-y²)+6/1(x²+y²)={1/6[2/1(x²-y)+3/1(x-y²)+6/1(

已知x2+y2-10x-6y+34=0,求（x-y/x+y）2÷x2-y2/xy×x2+2xy+y2/x2-xy的值.你好x²+y²-10x-6y+34=0（x-5）²+（y-3）²=0每项都大于等于

已知x2+y2+4x-6y+13=0求x2-2x\x2+3y2即(x²+4x+4)+(y²-6y+9)=0(x+2)²+(y-3)²=0所以x+2=y-3=0x=-2,y=3所以原式=(4+4)/(4

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

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)

x2-9y2+2x-6y因式分解.急x2-9y2+2x-6y=(x-3y)(x+3y)+2(x-3y)=(x-3y)(x+3y+2)4x^3-xy^2=x(4x^2-y^2)=x(2x+y)(2x-y)

x2-xy-6y2+x+7y-2(x+2y-1)(x-3y+2)方法：待定系数法观察整式可设：x^2-xy-6y^2+x+7y-2=(x+ay+b)(x+cy+d)将式子展开比较两边系数可得ac=-6;a+c=-1;bd=-2;b+d=1;

x2-2x+2y-y2因式分解x2-2x+2y-y2=﹙x＋y﹚﹙x－y﹚－2﹙x－y﹚=﹙x－y﹚﹙x＋y－2﹚x2-2x+2y-y2=x²-y²-2x+2y=(x+y)(x-y)-2(x-y)=(x-y)(x+y-2

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

因式分解(x2-y2)-(x-y)2快解(x²-y²)-(x-y)²=(x-y)(x+y)-(x-y)²=(x-y)[(x+y)-(x-y)]=(x-y)×2y=2y(x-y)=(x+y)(x-y)-

谁能帮解一下这个题,已知圆C1：x2+y2+2x+6y+6=0,圆C2：x2+y2-4x-8y+7=0,求两圆的圆心距.已知圆C1：x2+y2+2x+6y+6=0,圆C2：x2+y2-4x-8y+7=0,求两圆的圆心距.C1：x2+y2+2

已知圆C1:x2+y2-4x+6y=0,圆C2:x2+y2+2x+8y=0,求两圆的圆心距.圆C1:x²+y²-4x+6y=0（x-2）²+（y+3）²=13圆心坐标为（2,-3）圆C2:x²

已知实数x,y满足x2+y2-2x+2y=6求x2+y2的最值x2+y2-2x+2y=6(x-1)²+(y+1)²=2²所以可设x=1+2cosay=-1+2sina于是x²+y²=(1+2

已知x,y满足x2+y2-6x-2y+5=0,求x2+y2的最大值x2+y2-6x-2y+5=0(x-3)^2+(y-1)^2=5表示一个圆,圆心坐标（3,1）x^2+y^2表示圆上一点（x,y)到原点的距离的平方.画图就看出,最大距离是：

x2+x+y2/x+yx2是x^2?y2是y^2?原来的式子是（x^2+x+y^2)----------------(x+y)还是我理解错了?x2+x+y2/x+y中分数线？(x+y)^2+x-2xy/x+y=x+y+x-2xy=2x+y-