Question about distance vs time graph

here it says the acceleration is constant but velocity is increasing. can someone explain how we conclude the acceleration by the graph and whether it’s negative or positive? Thanks!!

2nd question
in this one acc is increasing but is it increasing negatively because velocity is negative or is it increasing positively?

For the first question, we can see that the graph is half of a parabola

You have to know the universal formula of a parabola : ax2 + bx + c
And know that here the graph is showing us distance vs. time → in other words x(t)

If you know how to pass from x(t) → v(t) → a(t) (derivation) you find your answer

For the second, the absolute value increases that’s why we say acceleration is increasing but yes it is increasing “negatively”