Given
t>0

Procedure
Speed would be:

This is the graph for the particle velocity. As you can see the graph corresponds to a parabola that has its minimum value when the time t is equal to 1.
The x-axis corresponds to the time and the y-axis corresponds to the velocity.
Now, with that minimum velocity-time, we can calculate the position using the initial equation that describes the particle position for each time.

The particle will be in position 4