Question

the common difference of an AP is 12 whose nth term is a n then find the value of a20-a17​​

Answer 1

Answer:

let the first term be a , and given that common difference , d =12

so, a20 = a +19d

and a17 = a+16d

now,

a20 -a17 = (a +19d) - (a +16d)

= 3d = 3× 12 = 36

formula used ,

an = a + (n -1)d.