Answer: B)
Step-by-step explanation:
If y = z then replace z for y in the second equation.
2 y + z = 12
2y + y = 12
3y = 12
y = 4
This also means z = 4.
Insert both of these values into the first equation:
x + y + z = 8 + 2sqr3
x + 4 + 4 = 8 + 2sqr3
x + 8 = 8 + 2sqr3
x = 2sqr3
