Help pls its a math question

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

Determine the number of outcomes in the event. decide whether the event is a simple event or not. upper a computer is used to select randomly a number between 1 and 9 comma inclusive. event upper b is selecting a number greater than 4. event upper b has nothing outcome(s). is the event a simple event? (yes or no) because event upper b has (fewer than, exactly, more than) one outcome.

How do you find the circumfrance of a circle?