In a flower bed,there are $23$ rose plants in the first row,$21$ in the second,$19$ in the third,and so on. There are $5$ rose plants in the last row. How many rows are there in the flower bed?

Do $1, -1, -3, -5, \ldots$ form an $AP$? If they form an $AP$,write the next two terms.

Find the sum of the first $40$ positive integers divisible by $6$.

Fill in the blanks in the following table,given that $a$ is the first term,$d$ is the common difference,and $a_{n}$ is the $n^{th}$ term of the $AP$:

$S.No.$	$a$	$d$	$n$	$a_{n}$
$(i)$	$7$	$3$	$8$	$...$
$(ii)$	$-18$	$...$	$10$	$0$
$(iii)$	$...$	$-3$	$18$	$-5$
$(iv)$	$-18.9$	$2.5$	$...$	$3.6$
$(v)$	$3.5$	$0$	$105$	$...$

The houses of a row are numbered consecutively from $1$ to $49$. Show that there is a value of $x$ such that the sum of the numbers of the houses preceding the house numbered $x$ is equal to the sum of the numbers of the houses following it. Find this value of $x$.

$1^{2}, 3^{2}, 5^{2}, 7^{2}, \ldots$ are $APs$? If they form an $AP,$ find the common difference $d$ and write three more terms.