Respuesta :

Arjinoodles

Answer:

-55

Step-by-step explanation:

the sqeuence seems to be subtracting by 2 everytime.

so it will be -1,-3,-5,-7,-9,-11,-13,-15,-17,-19,-21,-23,-25,-27,-29..

the answer will be 27*-2(-54) -1(because we start at -1 , not 0)

Luv2Teach

Answer:

Step-by-step explanation:

the formula for an arithmetic sequence that is explicit is

[tex]a_n=a_1+d(n-1)[/tex]  where [tex]a_1[/tex] is the first term (so -1), and d is the common difference (-2). n is the number position in the sequence. As soon as we find the formula or model for this sequence we can find any number term we want. Filling in the formula:

[tex]a_n=-1-2(n-1)[/tex] and we'll clean that up just a bit:

[tex]a_n=-1-2n+2[/tex] (I just distributed through the parenthesis) and a bit more to

[tex]a_n=-2n+1[/tex] and if we want the 21st term, fill in a 21 for n:

[tex]a_{21}=-2(21)+1[/tex] and

[tex]a_{21}=-42+1[/tex] so

[tex]a_{21}=-41[/tex]

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