Question

Find the first, fourth, and eighth terms of the sequence. A(n) = −5 ∙ 2x − 1

Answer 1

The first option.

Explanation:

The first term of the sequence would be...

A(1) = -5 * 2^(1 - 1)

= -5 * 2^0

= -5 * 1

= -5

The fourth would be...

A(4) = -5 * 2^(4 - 1)

= -5 * 2^3

= -5 * 8

= -40

The eighth would be...

A(8) = -5 * 2^(8 - 1)

= -5 * 2^7

= -5 * 128

= -640

So, the correct answer is the first option.

Hope this helps!

Answer 2

The answer is option A

Explanation:

The rule for the sequence is

`A(n) = 5. {2}^(x - 1)`

where x is the number of terms

For the first term

x = 1

That's

`A(1) = 5. {2}^(1 - 1)`

`A(1) = 5. {2}^(0)`

A(1) = 5(1)

A(1) = 5

For the fourth term

x = 4

`A(4) = 5. {2}^(4 - 1)`

`A(4) = 5. {2}^(3)`

A(4) = 5(8)

A(4) = 40

For the eighth term

x = 8

`A(8) = 5. {2}^(8 - 1)`

`A(8 ) = 5. {2}^(7)`

A(8) = 5(128)

A(8) = 640

Hope this helps you