已知方程组3x+7y+z=5;4x+10y+z=6,求x+y+z的值

问题描述:

已知方程组3x+7y+z=5;4x+10y+z=6,求x+y+z的值

3x+7y+z=5.➀
4x+10y+z=6.➁
➁-➀,得
x+3y=1.➂
➂乘以3,得
3x+9y=3.➃
➁-➃,得
x+y+z=6-3=3