Answer:
The answer is A (-3,4,6).
Step-by-step explanation:
1 Solve for z in -3x-4y+z=-1
z=3x-1+4y
2 Substitute z=3x-1+4y into 2x+y-z=-8
-x-3y+1=-8
3 Substitute z=3x-1+4y into x+8y-z=23
-2x+4y+1=23
4 Solve for x in -x-3y+1=-8
x=-3y+9
5 Substitute x=-3y+9 into z=3x-1+4y
z=-5y+26
6 Substitute x=-3y+9 into -2x+4y+1=23
10y-17=23
7 Solve for y in 10y-17=23
y=4
8 Substitute y=4 into z=-5y+26
z=6
9 Substitute y=4 into x=-3y+9
x=-3
10 Therefore,
x=-3
y=4
z=6
