{x:y=1:5 {y:z=2:3 {x+y+z=27 这一道..用3元一次解法

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{x:y=1:5 {y:z=2:3 {x+y+z=27 这一道..用3元一次解法
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{x:y=1:5 {y:z=2:3 {x+y+z=27 这一道..用3元一次解法
{x:y=1:5 {y:z=2:3 {x+y+z=27 这一道..用3元一次解法

{x:y=1:5 {y:z=2:3 {x+y+z=27 这一道..用3元一次解法
（1）x=y/5
(2)z=3y/2
带入（3）y/5+y+3y/2=27
y=10
带回去x=2,z=15

3个式子其中都含Y 你把前面两个里面的X和z全部用Y代替代入第三个里面就可以了

x=1/5y
z=3/2y
y+1/5y+3/2y=27
y=10
x=2
z=15

x/y=1/5=k
y/z=2/3
x+y+z=27
所以x=k y=5k z=7.5k
所以k+5k+7.5k=27
13.5k=27 所以K=2
所以x=2 y=10 z=15

x/2=y/3=z/5 x+3y-z/x-3y+z {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 方程组 (1) x+2y-3z=12 x-3y+2z= - 13 x-y-z=0 (2) x+ y=z 5x-y+z=18 2x+5y+3z= -1 x+Y+Z=1 X+3Y+7Z=-1 X+5Y+8Z=2x+Y+Z=1X+3Y+7Z=-1X+5Y+8Z=2 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. {x+y+z=1 x-2y+3z=5 2x-3y-3z=-8 2x-y+3z=3 {3X+Y-2Z=-1 X+Y+Z=5 x-y+z=-1 5x+2y-z=6 4x-3y+2z=-5 x+y+z=-5,3x+y+z=1,4x+3y+2z=-2快 3x+2y+z=14 ,x+y+z=10,z+2x+3y=1 5 3x-y+2z=-1 4x+y+z=5 x-2y-z=-2 {x+y+z=1 {x+3y+7z=-1 {x+5y+8z=2 x+y+z=-1 4x-2y+3z=5 y-z=8-2x x+y+z=2 x-3y+2z=1 2x+2y+z+5 要具体步骤.. x+y+z=1 4x+5y-z=6 x+2y-z=3 {x+y+z=1 {x+3y+7z=2 {x+5y+19z=4