A man invested $15,000. Part of the investment was put into an account that gave 7%, and part in an account that paid 6.5%. The interest earned was 1,520. How much was invested into each account?

just add up the interest earned by each investment. If x gets 7%, then the rest gets 6.5%

.07x + .065(15000-x) = 1520

There seems to be a problem here. Even if the whole 15,000 were invested at 7%, there would only be $1050 in interest.