Two accounts earn simple interest. The balance y (in dollars) of Account A after x years can be modeled by y=10x+500. Account B starts with $400 and earns 5% simple annual interest.

1)
A has a greater principal
2)
Principal of A is $500, the principal of B is $400, so A's principal is greater by $100
3)
Annual interest rate of A:
10/500 x 100
The interest rate of B is higher.
4) B's annual interest rate is 5% and A's annual interest rate is 2%, so B's is higher by 3%.
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