contestada

Algebra 1 Grade 9

Can anyone please help me with these arithmetic sequence question?

Use this for the next 3 questions:

Consider the arithmetic sequence 3, -10, -23, -36...

Write an equation for the nth term of the sequence.

an =


Find the 15th term in the sequence.

a15 =

Which term of the sequence is -114?

Respuesta :

Answer:

1.  [tex]a_{n} =16-13n[/tex]

2.  15th term is [tex]a_{15} =-179[/tex]

3.  10th term is -114

Step-by-step explanation:

1.  The nth term of the sequence is given by the formula:

[tex]a_{n} =a+(n-1)d[/tex]

Here, the first term a = 3 and the common difference d = -10 - 3 = -13

So, [tex]a_{n} =3+(n-1)(-13)[/tex]

[tex]a_{n} =3-13n+13[/tex]

[tex]=16-13n[/tex]


2.  To find the 15th term, put n = 15 in [tex]a_{n} =16-13n[/tex]

[tex]a_{15} =16-13(15)[/tex]

[tex]a_{15} =16-195[/tex]

= -179

Hence, the 15th term [tex]a_{15} =-179[/tex]


3.  To find the term which is -114, put  [tex]a_{n} =-114[/tex] in [tex]a_{n} =16-13n[/tex] and solve for n.

-114 = 16 - 13n

13n = 16+114

13n = 130

n = 130/13

= 10

Hence, the tenth term is -114.

Otras preguntas