Evaluate 9 - 8 over S when s is 4

What is the relationship between v(t), x(t), and a(t)? I assume that v(t) is a velocity and x(t) is distance traveled in relation to v(t) and a(t) is the acceleration in relation to v(t). So . . .

x(t) = ∫v(t)dt = ∫(8t + 25)dt = 4 + C
a(t) = d/dt(v(t)) = d/dt(8t+25) = 8