Question

Which rule will find the nth term of the arithmetic sequence -58, -65, -72, -86, …?

A.) an = -65 − 7n
B.) an = -65 + 7n
C.) an = 51 − 7n
D.) an = -51 + 7n
E.) an = -51 − 7n

Answer 1

the first term = a1 = -58
can you find the common difference ?

Answer 2

I can't

Answer 3

common difference d is the difference between the consecutive terms,
so, d= -65-(-58) = ... ?

Answer 4

-7?

Answer 5

yup!
d=-7
now just plug that in
\(a_n=a_1+(n-1)d\)
a1 = -58

Answer 6

it is an A.P with c,d =-65-(-72)=72-65=7
find tn by the formula tn=a+(n-1)d ,where a is first term and d is c.d

Answer 7

sorry c.d=-72-(-65)=-75+65=-7

Answer 8

So what do I do now?

Answer 9

plug in d=-7 , a1 = -58 in
\(a_n=a_1+(n-1)d\)

Answer 10

-66?

Answer 11

tn=-58+(n-1)*-7
tn=-58-7n+7=-51-7n

Answer 12

how ?
whats -58 -(-7) =... ?

Answer 13

-51. And sorry I typed he equation wrong slightly.

Answer 14

So it's E for the answer?

Answer 15

yes :)

Answer 16

thanks!

Answer 17

welcome ^_^