Simplify the following algebraic expression √882x^15y^24

A. 21x^7y^12√2x
B. 21x^7 √x
C. x^7 y^12 √21x
D. x^7 y^12 √2y

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!