Answer:
x = 2
Step-by-step explanation:
[tex]6x + 9y - 12 = 0 \\ 6x + 9 \times 0 - 12 = 0 \\ 6x + 0 - 12 = 0 \\ 6x - 12 = 0 \\ 6x = 12 \\ x = 2[/tex]