Help please anyone please

F(x) = (x^2 + 3x − 4) and g (x) = (x+4) find f/g and state the domain.

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

Which is f(5) for the function –2x2 + 2x - 3?