Step-by-step explanation:
It cannot be (4, -3) as there would be 2 outputs (3 and -3) for the input 4, therefore it becomes a one-to-many relationship and not a function.
I don't have a clue what this a0 at the right stands for, but if we neglected it, we can solve the problem.

So the answer would be 25.
Hope this helps.
Answer:
You did not include the price they bought the units at.
I will assume this price is $5.
= 5 * 1,000
= $5,000
Recording it will be:
Account Debit Credit
Merchandise Inventory $5,000
Accounts Payable $5,000
In simplified form it is 5x+5
The value of is 10 I think