Abcissa is x, and ordinate is y.
In this case the x is positive, and the y is negative.
Therefore, the answer is "positive, negative"
Answer: A
Step-by-step explanation:
To subtract vectors, you simply have to subtract correspondent coordinates.
So, if you have

the subtraction is simply

So, in your case, we have

The first 3 months are 250
6 months are 500
9 months are 1000
12 months are 2000
15 months are 4000
18 months are 8000
21 months are 16000
24 months are 32,000 which is two years