y的平方减2y减99等于0-搜答案-搜搜考试网

1/2再答：再问：谢谢了，问题解决了

该试可以这样写：(x-1)的平方加(y+2)的平方等于0.所以X等于1,Y等于-2.那2X加Y等于0了.

再问：姐姐，你多大啦，再答：20再问：哦哦，你家在哪呀，你当我姐姐好不好，？再问：^ω^再问：姐姐，你不说话我就当你默认了哈，！哈哈，姐，！再答：O(∩_∩)O再答：姐姐现在比较忙哦再问：

x^2-2x+y^2+6y+10=0x^2-2x+1+y^2+6y+9=0(x-1)^2+(y+3)^2=0x-1=0,y+3=0x=1,y=-3(x-y)/(x+y)=4/(-2)=-2

x+y-2=0x+y=2x²-y²=(x+y)(x-y)=6x-y=6/(x+y)=6/2=3x-y-5=3-5=-2

两圆方程整理成标准型C1：(x-1)²+y²=1C2：x²+(y-7)²=49-a∵两圆有三条公切线∴两圆外切连心线长为两圆半径之和∵C1(1,0)C2(0,7

x^2+2xy+y^2=25===>(x+y)^2=5^2===>x+y=±5(x-y)^2-3x+3y+2=0===>(x-y)^2-3(x-y)+2=0===>[(x-y)-1]*[(x-y)-2

x²+y²-4x-2y+5=0x²-4x+4+y²-2y+1=0(x-2)²+(y-1)²=0x-2=0x=2y-1=0y=1√(x+y)/

令a=y/xy=ax代入(1-a²)x²-4x+1=0x是实数,方程有解所以判别式大于等于016-4+4a²>=0a取任意实数所以没有最大值

x²-4y²+2x-4y=(x+2y)(x-2y)+2(x-2y)=(x-2y)(x+2y+2)

2Y^3-18Y^2-8Y+72=0Y^3-9Y^2-4Y+36=0Y^2(Y-9)-4(Y-9)=0(Y^2-4)(Y-9)=0(Y+2)(Y-2)(Y-9)=0Y1=-2Y2=2Y3=9

-y∧2-2y+3＝0y∧2+2y-3＝0y∧2+2y+1-4＝0（y+1）∧2＝4y+1＝±2y1＝1,y2＝-3

x^2+4x+y^2-2y+5=0(x^2+4x+4)+(y^2-2y+1)=0(x+2)^2+(y-1)^2=0x=-2,y=1x^2+y^2=(-2)^2+1^2=4+1=5

x²-4x-1=0x²-4x=1所以：(2x-3)²-(x+y)(x-y)-y²=4x²-12x+9-(x²-y²)-y²

因为（x+y）²>=0,(2y+1)>=0所以x+y=02y+1=0即y=-1/2x=1/2x-y=1

x+y=2x^2-y^2+4y=(x+y)(x-y)+4y=2x-2y+4y=2x+2y=2(x+y)=4