已知方程组 {3x+7y+z=3.15 4x+10y+z=4.20 急已知方程组 {3x+7y+z=3.15 4x+10y+z=4.20 求x+y+z的值将原方程组整理得:{ 2(x+3y)+(x+y+z)=3.15①3(x+3y)+(x+y+z)=4.20②①×3,得6(x+3y)+3(x+y+z)=9.45③ ②×2,得6(x+3y)+2(x+y+z)=

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已知方程组{3x+7y+z=3.154x+10y+z=4.20急已知方程组{3x+7y+z=3.154x+10y+z=4.20求x+y+z的值将原方程组整理得:{2(x+3y)+(x+y+z)=3.1

已知方程组 {3x+7y+z=3.15 4x+10y+z=4.20 急已知方程组 {3x+7y+z=3.15 4x+10y+z=4.20 求x+y+z的值将原方程组整理得:{ 2(x+3y)+(x+y+z)=3.15①3(x+3y)+(x+y+z)=4.20②①×3,得6(x+3y)+3(x+y+z)=9.45③ ②×2,得6(x+3y)+2(x+y+z)=
已知方程组 {3x+7y+z=3.15 4x+10y+z=4.20 急
已知方程组 {3x+7y+z=3.15 4x+10y+z=4.20 求x+y+z的值
将原方程组整理得:
{ 2(x+3y)+(x+y+z)=3.15①
3(x+3y)+(x+y+z)=4.20②
①×3,得6(x+3y)+3(x+y+z)=9.45③
②×2,得6(x+3y)+2(x+y+z)=8.40④
③-④得x+y+z=1.05
按照上述方法,已知方程组{x+y+z=11
x-3y-z=1
试求x+0.5z的值

已知方程组 {3x+7y+z=3.15 4x+10y+z=4.20 急已知方程组 {3x+7y+z=3.15 4x+10y+z=4.20 求x+y+z的值将原方程组整理得:{ 2(x+3y)+(x+y+z)=3.15①3(x+3y)+(x+y+z)=4.20②①×3,得6(x+3y)+3(x+y+z)=9.45③ ②×2,得6(x+3y)+2(x+y+z)=
x+y+z=11
x-3y-z=1
将原方程组整理得:
y+0.5z+(x+0.5z)=11 ①
-3(y+0.5z)+(x+0.5z)=1 ②
①×3,得 3(y+0.5z)+3(x+0.5z)=33 ③
③+②,得 x+0.5z=17/2