Chapter 11 - 11.2 - Arithmetic Sequences and Partial Sums - 11.2 Exercises - Page 786: 33

$a_1=2$ $a_2=-4$ $a_3=-10$ $a_4=-16$ $a_5=-22$

$a_n=a_1+(n-1)d$ $a_1=2,~~a_{12}=-64$ $a_{12}=a_1+(12-1)d$ $-64=2+11d$ $-66=11d$ $d=-6$ $a_2=2+(2-1)(-6)=2+1(-6)=2-6=-4$ $a_3=2+(3-1)(-6)=2+2(-6)=2-12=-10$ $a_4=2+(4-1)(-6)=2+3(-6)=2-18=-16$ $a_5=2+(5-1)(-6)=2+4(-6)=2-24=-22$