已知x+2y+3z=21,3x+2y+z=19,求x+y+z的值.

问题描述:

已知x+2y+3z=21,3x+2y+z=19,求x+y+z的值.

x+2y+3z=21 (1)
3x+2y+z=19,(2)
(1)+(2)得4x+4y+4z=40
两边除以4得
x+y+z=10