A particle moves in one dimension, and its position as a function of time is given by

x = (1.7 m/s)t + (−3.0 m/s2)t2.

(a) What is the particle's average velocity from t = 0.45 s to t = 0.55 s? (Indicate the direction with the sign of your answer.)

(b) What is the particle's average velocity from t = 0.49 s to t = 0.51 s? (Indicate the direction with the sign of your answer.)