Whats the answer can someone answer please

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

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling

The quadratic function h(t)=-16.1t^2+150 choose the graph representation