Question

The first term of an arithmetic sequence is -3 and the fifteenth term is 53. What is the common difference of the sequence?


14/13
25/7
4

Answer 1

so
a + 14d = 53
a = -3
So put a's value in the equation
And get d --> THE COMMON DIFFERENCE!! :D
Understood?

Answer 2

a + (n-1)d = The nth term!
And here n = 15 [RIGHT?]
sO 15th term = a + (15-1)d = a+14d
Getting me? :D

Answer 3

\(a_{15} = 53\) and \(a_1 = -3\)arithmetic sequence : \(\large a_n = a_1 +(n-1)d\) so \[\large 53 = -3 + (15-1)d\]\[\large 53 = -3 + 14d\]\[\large 56 = 14d\]\[\large \frac{56}{14} = d\]