{15x-3y+2z=1 3x+4y-z=-18 z=13

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{15x-3y+2z=1 3x+4y-z=-18 z=13
{15x-3y+2z=1 3x+4y-z=-18 z=13

{15x-3y+2z=1 3x+4y-z=-18 z=13
把z=13代入
15x-3y+26=1
15x-3y=-25 (1)
3x+4y-13=-18
3x+4y=-5 (2)
(1)×4+(2)×3
60x+9x=-100-15
x=-5/3
代入(1)
-25+3y=-25
y=0
所以x=-5/3,y=0,z=13

设商是A
则x²+2kx-3k²=A(x-1)
x=-1时x-1=0
则右边=0
所以左边也等于0
所以x=1
x²+2kx-3k²=1+2k-3k²=0
3k²-2k-1=0
(3k+1)(k-1)=0
k=-1/3,k=1

x+2y=3x+2z=4y+z 求x:y:z x+y/2=z+x/3=y+z/4 x+y+z=27 4x-9z=17 3x+y+15z=18 x+2y+3z=2x+y+z=26 x-y=1 2x+z-y=18 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 x+y+z=6 x+2y+3z=14 y+1=z (1)X+Y=15,Y+Z=-6,Z+X=7.(2)X+Y=-14,Y+Z=-7,Z+X=9.(3)X+Y=0,Y+Z=-1,Z+X=-1. 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 4x+2y+z=5,4x-2y+z=1,z=-15x+2y+z=12,4x+3y+z=13,z=3 x+2y+3z=10,4x+3y+2z=15则x+y+z= x+2y+3Z=10,4x+3y+2z=15,求x+y+z= 2x+y+3z=10,3x+4y+2z=15,则x+y+z= 4x+y+z=-3 2x+3y-4z=-10 x+2y-z=-1 2x+3y-z=9,x+y+z=15,5x-4y-z=0 x-y-z=1 2x+y-3z=4 3x-2y-z=-1 x+y-z=6 x-3y+2z=1 3x+2y-z=4 阿 x+y-z=6,x-3y+2z=1,3x+2y-z=4