x+y+z=2 3y-4z=-5 6z=3 .. nilai x-y adalah

6z = 3
z = 3/6
z= ½

3y - 4z = -5
3y - 4(½) = -5
3y - 2 = -5
3y = -3
y = -1

x + y + z = 2
x - 1 + ½ = 2
x = 3 - ½
x = 5/2

x - y
=>5/2 - (-1)
=>5/2 + 1
=>7/2

7/2 semoga membantu..