(5x squared minus 3x + 7) - (3x squared plus 4x - 5)

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?

If a baby uses 15 diapers in 2 days how many diapers will the baby use in a year

Which statement best describes how to determine whether f(x) = x squared- x +8 is an even function ?