Pleaase help i really need it same question on ss 1 and ss2

What is the vertex form of f(x) = x2 + 6x + 3

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!

The radius of a sphere is 3 inches. which represents the volume of the sphere?