Answer:
3, because
.
Explanation:
Looking at this graph, we can start to determine the equation for it.
The y-intercept of this graph is 9, therefore there will be a constant of 9.
We can find the slope by looking at rise over run. It vertically travels -1 for every 2 horizontally. So the slope is
.
Making this into an equation gets us
.
Now we can substitute 12 into this equation as x.
Hope this helped!