Chapter 1 - Some Basic Concepts of Arithmetic and Algebra - Chapter 1 Review Problem Set - Page 38: 68

$-44$

Substituting $a= 2 $ and $b= -5 ,$ the given expression, $ 2ab-3(a-b)+b+a ,$ evaluates to \begin{array}{l}\require{cancel} 2(2)(-5)-3(2-(-5))+(-5)+2 \\\\= -20-3(2+5)-5+2 \\\\= -20-3(7)-5+2 \\\\= -20-21-5+2 \\\\= -41-5+2 \\\\= -46+2 \\\\= -44 .\end{array}