Please help me with the questions
(EXPLAIN YOUR ANSWER PLEASE)

You and a friend race across a field to a fence and back. your friend has a 50-meter head start. the equations shown represent you and your friend's distances dd (in meters) from the fence tt seconds after the race begins. find the time at which you catch up to your friend. you: d=∣−5t+100∣d=∣−5t+100∣ your friend: d=∣−313t+50∣∣

Which graph corresponds to the function f(x) = x2 + 4x – 1?

What is the value of x in the this question ?