1. Solve for x, y, z in the following system:
2x-3y-2=z
y-x+z=1
-y-2z=7
The answers are: x=-7 y=-5 and z=-1 however I don't know how to go about this.
From the 3rd: y = -2z-7
in the 1st:
2x - 3(-2z-7) - z = 2
2x +6z +21 - z = 2
2x + 5z = -19 (#4)
in the 2nd:
-2z - 7 - x + z = 1
x + z = -8
2x + 2z = -16 (#5)
#4 - #5 :
3z = -3
z = -1
sub into y = -2z-7 ---> 2-7 = -5
sub into 2nd:
-5 - x - 1 = 1
-x = 7
x = -7
so , x = -7, y = -5 and z = -1