Question

过程请写出来

Answer 1

工作效率，即每天完成的进度。总的工作量为1
列式：(x+y)X10=1
(y+z)X6=1
(x+y+z)X4=1

Answer 2

3x-y+z=-2 (1)
2x+2y-z=-1 (2)
x-3y+z=-4 (3)

(1)+(2)
5x+y=-3 (4)

(2)+(3)
3x-y=3 (5)

(4)+(5)
8x=0
x=0

from (5)
0-y=3
y=-3

from (1)
3x-y+z=-2
0+3+z=-2
z=-5

ie
x=0, y=-3 , z=-5