ANSWER
x = -2, y = 7, z = 2
EXPLANATION
We are given a system of three equations:
2x + 3y - 4z = 9 ________(1)
4y - 6z = 16 ___________(2)
z = 2 ________________(3)
Since we have been given the value of z, from (3) we have that (2) becomes:
4y - 6(2) = 16
4y - 12 = 16
4y = 12 + 16 = 28
y = 28 / 4
y = 7
Put the values of y and z in (1):
=> 2x + 3(7) - 4(2) = 9
2x + 21 - 8 = 9
2x + 13 = 9
Collect like terms:
2x = 9 - 13 = -4
x = -4 / 2
x = -2
So, x = -2 and y = 7 and z = 2
