Aaron invested a total of $8,000 in two accounts. the first paid 7% interest annually the second account lost 1% annually at the end of the ?

Let $x be the sum invested in the first account, and $y be the sum invested in the second account.

System of equations:
x + y = 8000 …… [1]
7%x - 1%y = 380 …… [2]

[2]×100:
7x - y = 38000 …… [3]

[1]+[3]:
8x = 46000
x = 5750

Plug x = 5750 into [1]:
5750 + y = 2250

Ans: He invested $5750 in the first account, and $2250 into the second account.