The first term of an arithmetic sequence is -5, and the tenth term is 13. Find the common difference.
A) 8/9
B) 1.8
C) 2

Any help will be greatly appreciated!

Respuesta :

Basically use the number line ide, -5 to 13 is 18 apart. Ten apart, don't count the first one, so 9. 18/9= 2 apart C is your answer

Answer:

The common difference be 2.

Option(C) is corrct .

Step-by-step explanation:

As given

The first term of an arithmetic sequence is -5, and the tenth term is 13.

As the the terms in arithmetic sequence is in the form.

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

[tex]a_{n} = n^{th}\ term[/tex]

[tex]a_{1} = 1^{th}\ term[/tex]

d is the common difference .

As [tex]a_{1} = - 5[/tex]

n = 10

[tex]a_{10} = 13[/tex]

Put in the above

[tex]a_{10} = a_{1} + (10 - 1)d[/tex]

[tex]13 = -5 + (10 - 1)d[/tex]

[tex]13 + 5 = 9d[/tex]

[tex]18= 9d[/tex]

[tex]d = \frac{18}{9}[/tex]

d = 2

Therefore the common difference be 2.

Option(C) is corrct .