We invested $7000 invested in two accounts, we don't know how much exactly is in each account, therefore we will assign variables to these amounts. The amount invested in the "8%" account is "x", while the other one is "y". The sum of these two numbers must be equal to $7000, therefore:
The sum of interest of each account should be equal to 580, therefore:
We need to solve the system in order to determine the values.
Now we can replace the value of "x" in the first equation to determine the value of "y".
The values are 6500 in the 8% account and 500 in the 12% account.