Answer:
(r-1)d
Explanation:
The nth term of any arithmetic series is obtained using the formula:
[tex]T_n=a+(n-1)d[/tex]
For any row, r (where r is the number of rows)
The difference between the first and last numbers in any row will be:
[tex](r-1)d[/tex]
Where:
• d=common difference
• r=number of rows.
For an illustration, the difference between the first and last term in the fourth row:
Number of rows = 4
Common difference = 5
[tex]\begin{gathered} (4-1)(5) \\ =3(5) \\ =15 \end{gathered}[/tex]
Check: 46-31 = 15
