解三元一次方程组:5x+y+z=1(1) 2x-y+2z=1(2) x+5y-z=-4(3) 急解三元一次方程组:5x+y+z=1(1)2x-y+2z=1(2)x+5y-z=-4(3)

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解三元一次方程组:5x+y+z=1(1) 2x-y+2z=1(2) x+5y-z=-4(3) 急解三元一次方程组:5x+y+z=1(1)2x-y+2z=1(2)x+5y-z=-4(3)
解三元一次方程组:5x+y+z=1(1) 2x-y+2z=1(2) x+5y-z=-4(3) 急
解三元一次方程组:
5x+y+z=1(1)
2x-y+2z=1(2)
x+5y-z=-4(3)

解三元一次方程组:5x+y+z=1(1) 2x-y+2z=1(2) x+5y-z=-4(3) 急解三元一次方程组:5x+y+z=1(1)2x-y+2z=1(2)x+5y-z=-4(3)
①+③:6x+6y=-3,得2x+2y=-1 ④
①*2-②:8x+3y=1,⑤
④*4-⑤:5y=-5,得y=-1
代入④:x=(-1-2y)/2=1/2
代入①:z=1-y-5x=1+1-5/2=-1/2
解为x=1/2,y=-1,z=-1/2