100 POINTS! please help me out

which describes all possible values of f(x) in the function f(x) = square root x/2

Which is a true statement about an exterior angle of a triangle a. it is formed by two segments that are not sides of the triangle, b. it forms a linear pair with one of the interior angles of the triangle, c. it is complementary to one of the interior angles of the triangle. d. it is formed by two segments that are sides of the triangle.

The graph shown is the graph of which function?

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