What is the equation for time when using a position-time graph?
and
what is the equation for displacement when using a velocity-time graph?

This really depends on the graph but to approach these types of problems you can go about it this way (check explanation)...

Explanation:

(1) What is position?

Where is the object's location at?

If slope is zero, velocity is zero (straight line)

Slope positive, velocity is constant/ positive (linear line positive)

Object is accelerating.. curve upwards.

Steeper the slope, higher the speed

(2) What is velocity?

What are velocity vs. time graphs? - Khan Academy

the word that best describes martin luther king jr.'s tone in the video is dignified

martin luther king, jr. was a social activist and baptist minister who played a key role in the american civil rights movement from the mid-1950s until his assassination in 1968. the video shows his manner and attitude having or showing a composed or serious manner that is worthy of respect so dignified is the correct answer