Answer:
2
Explanation:
You can rewrite thosee two equations as -9x+12=-6, because f(x)=f(x)
Now isolate x
-9x+12=-6
-9x+12-12=-6-12 (subtract 12, subtraction property of equality)
-9x=-6-12
-9x=-18 (simplify)
-9x/-9=-18/-9 (divide by 9, division property of equality)
x=2