Question 1131527

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
<pre>Specific term of an AP: {{{matrix(1,3, a[n], "=", a[1] + (n - 1)d)}}} 
{{{matrix(1,3, a[15], "=", - 3 + (15 - 1)d)}}} --- Substituting {{{matrix(2,3, 15, for, n, - 3, for, a[1])}}}
53 = - 3 + 14d ---------- Substituting {{{matrix(1,3, 53, for, a[15])}}}
56 = 14d ------------ Adding 3 to both sides
d, or common difference = {{{highlight_green(matrix(1,3, 56/14, "=", 4))}}}