help me on this please !!

Step-by-step explanation:
Hey, there !!
It's simple lets get started with simple solution,
Given the sequences are,
10,8,6,4....
Then,
common diifference= 2
now, we have formula,
[tex]an = a1 + d(n - 1)[/tex]
[tex]or \: an= 10 + 2(n - 1)[/tex]
[tex]or \: an \: = 10 + 2n - 2[/tex]
[tex]an \: = 2n + 8[/tex]
[tex]or \: an = 2(n + 4)[/tex]
Therefore, The answer is an = 2( n+4) or, 10+2(n-1)...
{ note: 2(n+4) is simplified form of 10 +2(n-1).}
Hope it helps...