Answer:
4
Step-by-step explanation:
To get the value of z, we need to reduce the system of equation into two and 2 unknowns;
Add 1 and 3:
y - 12y + z + 8z = 2+12
-11y + 9z = 14 ....... 4
Also Multiply equation 1 by 3 and subtract from 2
Eqn 1 * 2 will give 3x + 3y + 3z = 6
Subtract from eqn 2;
3y-(-2y)+3z-2z = 6-(-8)
5y+z = 14 ....5
Solve 4 and 5
-11y + 9z = 14 * 5
5y+z = 14 * 11
________________
-55y + 45z = 70
55y + 11z = 154
Add both
45z+11z = 70+154
56z = 224
z= 224/56
z = 4
Hence the value of z is 4
