7x-3y+2z=15 6x+2y-z=13 3x-2y+2z=10 【方程组解】

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7x-3y+2z=15 6x+2y-z=13 3x-2y+2z=10 【方程组解】
7x-3y+2z=15 6x+2y-z=13 3x-2y+2z=10 【方程组解】

7x-3y+2z=15 6x+2y-z=13 3x-2y+2z=10 【方程组解】
7x-3y+2z=15 (1)
6x+2y-z=13 (2)
3x-2y+2z=10 (3)
(1)+2(2)
19x+y=41
(1)-(3)
4x-y=5
23x=46
x=2
y=3
z=5

7x-3y+2z=15,14x-6y+4z=30,
6x+2y-z=13,18x+6y-3z=39,32x+z=69,
3x-2y+2z=10 ,9x+z=23,23x=46,x=2,z=5,y=3

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设①7x-3y+2z=15 ②6x+2y-z=13 ③3x-2y+2z=10
①+②×2：（7x-3y+2z）+(6x+2y-z）×2=15+13×2 → 19x+y=41.......④
①-③=（7x-3y+2z）-（3x-2y+2z）=15-10 →4 x-y=5........⑤
④+⑤=（19x+y）+（4x-y）=41+5 → 23x=46→x=2
将x=2代入⑤ → 4×2-y=5 → y=3
将x=2和y=3代入③ → 3×2-2×3+2z=10 → z=5
则x=2 y=3 z=5

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(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 x+y+z=6 x+2y+3z=14 y+1=z 若X:Y:Z=5:6:7那么(Y-X):(Y+Z)和(X+2Y+3Z):(3X+2Y+Z) 2x-3y-z=-6 7x-y+2z=-17 x-y+z=-6 方程组3x-y-z=9,2x+y-2z=6,x+y+z=15 2x+5y+4z=6,3x+y-7z=-4,x+y-z=? 已知2x+5y+4z=6 3x+y-7z=-4求x+y-z 5x+3y+2z=2011 4x+6y+7z=2012 求x+y+z 1.{x:y:z=3:4:5 2x+3y-5z=-142.{x-y-z=-1 3x+5y+7z=11 4x-y+2z=-13.{x+y=1 x+z=0 2x+y+2z=44.{x-y+z=-3 2x-y-z=-2 -3x+y+z=-15.{x-y+z=-3 3x+y-4z=6 2x+y-z=36.{x-2y+5z=16 2x+y-5z=7 2x-y+z=38 解三元一次方程组 ①2x-y+z=1 3x+y -2z=2 X+2y-z=3 ②x-4y+z=-3 2x+Y-Z=18 X-Y-Z=7 ③4x+4y+2z=7 6X-4y-z=6 2x-y+z=1 6x+3y-2z=108,9x+7y-3z=212,3x-2y+5z=38,求x,y,z 已知4x-3y-6z=0,x+2y-7z=0,求5x+2y-z/2x-3y-10z 若4x-3y-6z=0,x+2y-7z=0,则x+y+z/3x-y+z=? 已知：4x-3y-6z=0,x+2y-7z=0.求出x-y+z÷x+y+z=? 已知4x-3y-6z=0,x+2y-7z=0,则x-y+z/x+y+z=_________ 已知4x-3y+6z=0 x+2y-7z=0 则x-y+z/x+y-z=?