I need explanation

Q1) a) Given f (x) = x2 - 9 and g(x) = v9 - x2, find the composition (f . g)(x) and the domain of (f . g) (x). b) Solve for x the following equations: a) 22x - 2*+2 - 25 = 0. b) In x 2 + 5 = 3 In x. c) Use the definition of the derivative to find the derivative of g(x) = x3 - 2x2+ x-1. d) ] Let f (x) = vx2 -2x+ 2+ vx2 - 6x + 13. Find the point(s) on the graph of f at which the tangent line is horizontal