Chapter 4 - Section 4.2 - Adding and Subtracting Polynomials - 4.2 Exercises - Page 286: 84

$-19p+14$

Removing the grouping symbols and then combining like terms, the given expression, $ [2p-(3p-6)]-[(5p-(8-9p))+4p] ,$ simplifies to \begin{array}{l}\require{cancel} [2p-3p+6]-[(5p-8+9p)+4p] \\\\= [2p-3p+6]-[5p-8+9p+4p] \\\\= 2p-3p+6-5p+8-9p-4p \\\\= (2p-3p-5p-9p-4p)+(6+8) \\\\= -19p+14 .\end{array}