x-2y+3z=0,3x+2y+5z=12,2x-4y-z=(-9)
来源:学生作业帮 编辑:大师作文网作业帮 分类:数学作业 时间:2024/10/05 08:38:48
x-2y+3z=0,3x+2y+5z=12,2x-4y-z=(-9)
x-2y+3z=0 (1)
3x+2y+5z=12 (2)
2x-4y-z=(-9) (3)
(1)式+(3)式得:
3x-6y+2z=-9 (4)
(2)式-(4)式得:
8y+3z=21 (5)
(1)式乘以3得:
3x-6y+9z=0 (6)
(2)式- (6)式得:
8y-4z=12 (7)
(5)式 -(7)式得:
7z=9,z=9/7;
代入(7):8y-36/7=12;
y=15/7;
把z=9/7;y=15/7;代入(1)
x-30/7+27/7=0
x=3/7;
所以解为:
x=3/7;
y=15/7;
z=9/7
3x+2y+5z=12 (2)
2x-4y-z=(-9) (3)
(1)式+(3)式得:
3x-6y+2z=-9 (4)
(2)式-(4)式得:
8y+3z=21 (5)
(1)式乘以3得:
3x-6y+9z=0 (6)
(2)式- (6)式得:
8y-4z=12 (7)
(5)式 -(7)式得:
7z=9,z=9/7;
代入(7):8y-36/7=12;
y=15/7;
把z=9/7;y=15/7;代入(1)
x-30/7+27/7=0
x=3/7;
所以解为:
x=3/7;
y=15/7;
z=9/7
x=y/z=z/3,x+y+z =12,求2x+3y+4z是多少,
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
x/2=y/3=z/5 x+3y-z/x-3y+z
如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y,
2x+5y+4z=0,3x+y-7z=0,则x+y-z=?
已知方程组4x-5y+2z=0 x+2y=3z 则x:y:z
已知3x-2y-5z=0,2x-5y+4z=0,且x,y,z均不为0,求3x*x+2y*y+5z*z/5x*x+y*y-
已知x,y,z 大于0,x+y+z=2,求证 xz/y(y+z)+zy/x(x+y)+yx/z(z+x)大于等于2/3
已知x+4y+3z=3x-2y-5z=0,求x+2y-z/2x-3y+7z的值
已知{3x+4y+5z=0,2x+3y-4z=0,求x+y+z/x-y+z的值.
已知2x+3y-4z=0,3x+4y+5z=0,求x+y+z/(除以)x-y+z的值.
已知2x+3y-4z=0,3x+4y+5z=0,求x+y+z/x-y+z的值.