若x y互为相反数,且x加3y=4
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x+y=03x+y分之7x+3y=?=2x+x+y分之4x+3x+3y=2x分之4x=2
/>(x+y+3)(x-y-2)=0x,y互为相反数则x+y=0...(1)带入上式3(x-y-2)=0x-y=2...(2)联立(1)(2)得x=1,y=-1
XY=1m+n=0m/n=-1所以XY(m+n)-n/m+2XYZ=1*0-(-1)+2Z=1+2Z当z=3时,XY(m+n)-m分之n+2XYZ=7当Z=-3时,XY(m+n)-m分之n+2XYZ=
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,
(x+4)²-(y+4)²=16(x+4+y+4)(x+4-y-4)=16x+y=0x-y=2x+y=0∴x=1y=-14x²-y=5
∵m,n互为相反数,x,y互为倒数,且|a|=1∴m+n=0,xy=1,a=±1,a^2=1∴a²xy+b²(m+n)+a=1*1+0*b^2±1=1+0±1=2或0望采纳
X-2y=0,x+y-3=0解得x=2,y=1所以xy=2.
XY互为相反数,x+y=0x-y=2x(x+y+3)(x-y-2)=3(2x-2)=62x-2=2x=2
∵|3-x|与|x+y|互为相反数∴|3-x|+|x+y|=0∵|3-x|≥0,|x+y|≥0∴3-x=0x+y=0解得:x=3,y=-3∴(x-y)/xy=【3-(-3)】/3x(-3)=-2/3
y=-x5x+3x=4x=1/2y=-1/2xy=-1/4
由于开根号和绝对值均大于等于0,两者互为相反数,也就是都等于0,因此X为-2,Y为3,因此XY等于-6
x,y互为相反数,(x+1)²-(y+3)²=8,则xy=-4
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
xy/3m+(a+b)/2009=1/6+0/2009=1/6
x+y=0ab=1所以1/2(x+y)+3ab=3
a*xy+b*(m+n)+a=1*1+b^2*0+a=1+aa=1时原式为2a=-1时,原式为0
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
∵|x+3|与|y+2|互为相反数且根据绝对值定义:|x+3|≥0|y+2|≥0∴x+3=0,y+2=0解得:x=-3y=-2∴原式=(-3)×(-2)-(-3)÷(-2)=6-1.5=4.5
(x-3)+/y+1/=0有题可知x-3=0,/y+1/=0则x=0+3=3,y=0-1=-1所以xy=3*(-1)=-3