Please explain this well i don't understand (55 points)

Solve for x, y, and z. show all steps.

For f(x)=2x+1 and g(x)= x^2 -7, find (f•g)(x)

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?