已知xy互为相反数,且(2X-3)^2-(2Y=1)=48,求xy的值
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(x+y-1)^2与|2x-y+4|互为相反数,(x+y-1)^2>=0,|2x-y+4|>=0,互为相反数则x+y-1=0;2x-y+4=03y=6y=2,x=-1y^x=2^(-1)=1/2,y^
(X-3)^2>=0,√x+y-5>=0(X-3)的平方与√x+y-5互为相反数,说明(X-3)^2=0,√x+y-5=0得x=3,y=2√2xy+13=√(2*3*2+13)=5
(x-3)^2>>0√(x+y-5)>>0√(x+y-5)+(x-3)^2=0所以:x-3=0x=3x+y-5=0y=2√(2xy+13)=√(2*3*2+13)=√25=5
因为(xy-1)²为非负数√2x-y4也为非负数又他们互为相反数所以xy-1=0.2x-y4=0,解二元一次方程得x=-1.y=2xy=-2xy的负倒数为1/2
∵x-3的2次方与根号x+y-5互为相反数∴(x-3)²+√(x+y-5)=0∴x-3=0x+y-5=0x=3y=2∴√(2xy+13)=√(2*3*2+13)=√25=±5
因为(x+y-1)平方与根号2x-y+4互为相反数所以(x+y+1)²+根号2x-y+4=0因为平方和开方都是非负数所以只有2式子都等于0时等式才成立X+Y-1=02X-Y+4=0X=-1Y
∵|x-6|+(x-2y)²=0 ∴|x-6|=0 (x-2y)²=0 ∴x-6=0 x-2y=0 ∴x=6 y=3 ∴√(2xy+13) =√(36+13) =√49
即x+y=0y=-x所以(2x-3)²-(-2x+1)²=484x²-12x+9-4x²+4x-1=488x=-40x=-5y=5所以xy=-25再问:对不起,
原题=(2x+y)(x+2y)=20112x²+xy+4xy+2y²=20112(x+y)²+xy=2011因x,y为互为相反数,所以x+y=0xy=2011
∵(x-3)的平方与x+y-5算术平方根互为相反数,且(x-3)²≥0,x+y-5算术平方根≥0∴x-3=0,x+y-5=0∴x=3∴y=2∴2xy+13=2×3×2+13=25∴2xy+1
因为(x+y-√3)²与√(2x-y)互为相反数且(x+y-√3)²和√(2x-y)均为非负数可得:(x+y-√3)²=0,√(2x-y)=0x+y=√32x-y=0解得
x与y互为相反数∴x+y=0(2x+y)(2y+x)=2011(x+y+x)(x+y+y)=2011∴xy=2011
xy互为相反数,所以x+y=0(x+2)2-(y+2)2=4(x+2+y+2)(x+2-y-2)=4(x+y+4)(x-y)=44(x-y)=4x-y=1
x、y互为相反数,x+y=0(2x+y)(x+2y)=(x+x+y)(x+y+y)=xy=1/2011xy=1/2011.再问:O(∩_∩)O谢谢!
|x+y-1|+|x+2|=0x+y-1=0,x+2=0x=-2,y=3ab=1所以xy+ab=-6+1=-5
因为(x-y-1)^2≥0;根号2x+y-7≥0二者互为相反数因此,二者必须都为0x-y-1=02x+y-7=0解方程组得,x=8/3,y=5/3所以,根号2xy+13=根号下(197/9)=3分之根
X、y互为相反数,则x+y=0(2x+y)(x+2y)与1/2011的相反数相等,则(2x+y)(x+2y)=-1/2011则(x+x+y)(x+y+y)=-1/2011(x+0)(0+y)=-1/2
xy互为相反数∴x+y=0x=-y把x=-y代入(x+2)2-(y+2)2=4得y²-4y+4-y²-4y-4=4-8y=4∴y=-1/2xy=-y²=-1/4
x+y=0(x+2)的次方-(y+2)的次方=4(x+y+4)(x-y)^2=4(x-y)^2=1(x-y)^2=(x+y)^2-2xy=1-2xy=1xy=-1/2