For the following graphs of position versus time (in one dimension), please determine the acceleration.

Options are, positive acceleration, negative acceleration, first negative then positive, first positive then negative, and no acceleration

graphs in pics

ibb.co/1Z8MnZR
ibb.co/9tD3jk8

positive acceleration means the slope is increasing

so, for the first graph,
since the slope starts out positive, decreases to zero at the top, then gets increasingly steep downward, acceleration is negative at all times

Now you try the others. Come back if you get stuck.