Khalid wrote the sequence below.

x-1, -2x+2, 4x-4, -8x+8

Which formula can be used to find the 10th term of the sequence?
A. a10=(x-1)*(-2)^10-1
B. a10=(x-1)^10-1
C. a10=(x-1)*(2)^10-1
D. a10=(x-1)*(-2)^10

Respuesta :

Formula A can help you find the 10th term.
I hope this Helps you
ANSWER

The 10th term of the sequence can be found using the formula,

[tex]a_{10} =(x - 1)( - 2) ^{ 10- 1} [/tex]

EXPLANATION

The first four terms of the geometric sequence were given as,

[tex](x-1),(-2x+2),(4x-4),(-8x+8)[/tex]

We can determine the common ratio using any two subsequent terms.

The common ratio is,
[tex]r= \frac{ - 2x + 2}{x - 1} [/tex]

This implies that,
[tex]r= \frac{ - 2(x - 1)}{x - 1} = - 2[/tex]

Also, the first term of the sequence is,

[tex]a_1=x - 1[/tex]

The general term of the sequence is given by,

[tex]a_n=a_1(r) ^{ n- 1} [/tex]

We substitute the first term, the common ratio and [tex] n= 10[/tex]
in to the general term to get,

[tex]a_{10} =(x - 1)( - 2) ^{ 10- 1} [/tex]

The correct answer is option A.