Consider the process of improving the performance of a program by optimizing some of the code in the program and running it in an enhanced (i.e., optimized) form. Suppose that optimized instructions run 20 times faster than sequential. a. Derive the speedup equation when x% of the instructions are optimized. b. Determine the percentage of code that must be optimized to get a speedup of 2,5 , and 10 respectively. c. If 25% of the code cannot be optimized (due to the inherently sequential nature such as I/O etc.), then what is the maximum speedup you can achieve