已知3y的平方减2y加6的值是8,那么代数式二分之三y的平方减y加一的值是
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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
3x^2+2xy+y^2-6x-6y+9=0(x+y)^2-6(x+y)+9=0(x+y-3)^2=0x+y=3
x²+y²+4x-6y+13=0(x²+4x+4)+(y²-6y+9)=0(x+2)²+(y-3)²=0x+2=0y-3=0x=-2y=3当
x^2+y^2=6y-4x-13x^2+4x+4+y^2-6y+9=0(x+2)^2+(y-3)^2=0x=-2y=3x^2-y^2=(-2)^2-3^2=4-9=-5
x^2+y^2+2x-6y+10=0(x^2+2x+1)+(y^2-6y+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
原等式可化为:x²-2xy+y²+6(x-y)+9+y²=0即:(x-y)²+6(x-y)+9+y²=0(x-y+3)²+y²=0
x=1,y=-3再问:过程再答:化简一下就得到方程(x-1)2+(y+3)2=0.这里的2表示平方啊,不知道怎么打平方。很明显只有x=1,y=-3才满足啊。
x²+2x+1+y²-6y+9=0(x+1)²+(y-3)²=0∴x+1=0y-3=0∴x=-1y=3
由x²+y²-2x+4y+5=0(x²-2x+1)+(y²+4y+4)=0(x-1)²+(y+2)²=0∴x=1,y=-2x-2y=1+4=
x+y-2=x^2+axy+by^2-5x+y+6x+y-2是x^2+axy+by^2-5x+y+6的因式当x+y-2=0时,x^2+axy+by^2-5x+y+6=0令x=y=1,x+y-2=0x^
x²-2x+y²+6y+10=0(x²-2x+1)+(y²+6y+9)=0(x-1)²+(y+3)²=0∴x-1=0,y+3=0∴x=1,y
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+y²+z²-2x-4y-6z+14=0(x-1)²+(y-2)²+(z-3)²=0因为每个平方数都≥0,它们之和为0,那么它们每个都为
原式=(x-3)^2+(y+1)^2=0所以x=3,y=-1所以3√(x*x-y*y)=3√(9-1)=2
2y^2+3y+7=84y^2+6y+14=164y^2+6y-9=16-14-9=-7
4y²-2y+5=7,则4y²-2y=2,即2y²-y=1.则3y-6y²+1=-3(2y²-y)+1=-3+1=-2
x^+y^-8x-6y+25=0(x-4)^+(y-3)^=0x=4y=33x+4y=3*4+4*3=24^表示平方追问:怎么得出(x-4)^+(y-3)^=0回答:x^+y^-8x-6y+25=0x
-3y²+2y-6=-8,所以-3y²+2y=-2,-3/2y²+y-1=1/2*(-3y²+2y)-1=1/2*(-2)-1=-2