Solve this polynomial (6x^2-5x)-(2x^2+3x-2)

Can someone me and do the problem plz so i can understand it more better

Dakota earned $7.50 in interest in account a and $18.75 in interest in account b after 15 months. if the simple interest rate is 4% for account a and 5% for account b, which account has the greater principal? explain. to make it a little easier, there is an image. good luck!

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