解三元一次方程组,要过程!!!
{x+y+z=6
{3x-y=3
{2x+3y-z=12
要过程!急!
{x+y+z=6
{3x-y=3
{2x+3y-z=12
由2式得,y=3x+3
代入1式,得x+3x+3+z=6, z=3-4x
把y,z代入3式
2x+3*(3x+3)-(3-4x)=12
2x+9x+9-3+4x=12
15x=6
x=3/5
y=3*3/5+3=24/5
z=3-4*3/5=3/5
解:
{x+y+z=6
{3x-y=3
{2x+3y-z=12
3x+4y=18
y=3
x=2
z=1
-----------
{x+2y-z=7
{2x+y+z=2
{3x+4y+z=7
x+3y=5
4x+6y=14
x=2
y=1
z=-3
---------------
{5x+4y+z=0
{3x+y-4z=11
{x+y+z=-2
4x+3y=2
15x+11y=7
y=2
x=-1
z=-3
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