The difference between two consecutive terms of an $A.P.$ is denoted by.........

For an $A.P.$,the $6^{th}$ term is $19$ and the $17^{th}$ term is $41$. Find the $40^{th}$ term of the $A.P.$

The $n^{th}$ term of an $A.P.$ is given by $T_{n} = 10 - 6n$. Find the sum of the first $n$ terms of the $A.P.$

For a given finite $A.P.$,$a=2, n=8$ and $S_{8}=72$. Then,$l=........$

Find the $20^{\text{th}}$ term of the $AP$ whose $7^{\text{th}}$ term is $24$ less than the $11^{\text{th}}$ term,first term being $12$.

The $26^{\text{th}}$,$11^{\text{th}}$,and the last term of an $AP$ are $0$,$3$,and $-\frac{1}{5}$,respectively. Find the common difference and the number of terms.