21,19,17,15,13, how to put this sequence in an explicit form

This sequence is arithmetic because we add -2 to each term to get the next term. So d = -2 is the common difference.

The starting term is a1 = 21

Therefore the nth term formula is

an = a1 + d(n-1)

an = 21 + (-2)(n-1)

an = 21 - 2n + 2

an = -2n + 23 which is the final answer

note how plugging in n = 1 leads to

an = -2n + 23

a1 = -2*1 + 23

a1 = -2 + 23

a1 = 21 which is the proper first term we want

So that helps partially confirm the answer. I'll let you check the other terms.

The value of the 3 in the tenths place =

The value of the 3 in the tens place = 30

Step-by-step explanation:

Given Number =   730.31

So the question says :  how does the value of the 3 in the tenths place compare to the value of the 3 in the tens place?

This concept is refereed to as Place Value. Place Value explains the position of a digits  holds in a particular number.

in 730.31

The .3 here holds the position of a tenth and it is represented as : which makes it .3

The value of the 3 in the tenths place =

The other 3 holds the position of tens and it is represented as : 3 × 10 = 30

The value of the 3 in the tens place = 30