The graph represents the height, in meters, of a feather dropping to the ground, in minutes. What does the y-intercept mean?

Which approach to the theory-and-research cycle does the following sequence reflect: (1) specific observations suggest generalizations, (2) generalizations produce a tentative theory, (3) the theory is tested through the formation of hypotheses, and (4) hypotheses may provide suggestions for additional observations?

Whats are the trickiest steps to do when adding or subtracting rational expressions? how does knowledge of rational numbers u in adding and subtracting rational expressions?

Which concept can be used to prove that the diagonals of a parallelogram bisect each other?