Does 21.6,28.8,36 equal a right triangle

Evaluate the following expression 1/3^2

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!

Which describes the difference between the graph of f(x)=x^2 and g(x)=-(x^2-2)