Chapter 1.2, Problem 51PS

Consider the following pattern:

$\begin{array}{rll}9\times 1-1& =& 8\\ 9\times 21-1& =& 188\\ 9\times 321-1& =& 2888\\ 9\times 4321-1& =& 38888\end{array}$

a. Use this pattern and inductive reasoning to find the next problem and the next answer in the sequence.

b. Use this pattern to find $9\times 987654321-1$

c. Use this pattern to find $9\times 10,987654321-1$