HELP HURY ITS OVERDUEEE

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!

Write as a product: ac^2–ad+c^3–cd–bc^2+bd

Can you explain how a table can be used to find a rate of change?