What is the geometric mean of 6 and 13

Which statement accurately describes how to perform a 90° clockwise rotation of point a (1,4) around the origin?

Someone which statements are true? check all that apply.

If (x + 8) is a factor of f(x), which of the following must be true? both x = –8 and x = 8 are roots of f(x). neither x = –8 nor x = 8 is a root of f(x). f(–8) = 0 f(8) = 0