Your question go from trig to inverse to sketching to combining functions to completing the square, topics which tend to be distinct from each other in high school. If you cannot do them I would suggest going back to the basics...

As for where to start, start with the graphs 7,8,9...

7) root functions and quadratics -- the key is to use transformations and algebraic manipulation (factor, complete the square) to find key features such as maximums and minimums and points at which the graph crosses the x-axis. 7(d) is a rational function, find a common base.

8) Inverse functions have the property of x = y, the opposite of the normal y=x. If it's a rational function areas where the denominator = 0 are undefined so include them as restrictions.

9) Sketch it using the techniques in 7). (a) break even are points where the function = 0. (b) Profit maximization occurs where the function is at it's max, so complete the square to get the vertex.