ANSWER:
(a) 2 boxes
(b) 132 boxes
STEP-BY-STEP EXPLANATION:
We can write a function based on the following:
[tex]a_n=a_1+d\cdot(n-1)[/tex](a) It would be an arithmetic sequence, we replace each value and it would be as follows:
[tex]\begin{gathered} a_6=42+-8\cdot(6-1) \\ a_6=42-8\cdot5 \\ a_6=42-40 \\ a_6=2 \end{gathered}[/tex]To calculate the number of boxes in the entire display, we follow the following formula:
[tex]\begin{gathered} s=\frac{n}{2}\cdot(2\cdot a_1+(n-1)\cdot d) \\ \text{ in this case would be:} \\ s=\frac{6}{2}\cdot(2\cdot42+(6-1)\cdot-8) \\ s=3\cdot(84-40) \\ s=3\cdot44 \\ s=132 \end{gathered}[/tex]