x1+2x2+3x3=-7 2x1-x2+2x3=-8 x1+3x2=7。请用初等变换求解

Question

x1+2x2+3x3=-7 2x1-x2+2x3=-8 x1+3x2=7。请用初等变换求解，我算了很多遍了真心难算

Answer 1

x+2y+z=8 (1)
2x+3y+z=11 (2)
x+3y+3z=16 (3)
(3)-(1),得 y+2z=8
2*(1)-(2),得 y+z=5
两个等式相减,z=3 所以y=2,x=1
方程组的解是 x1=1,x2=2,x3=3 .追问

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