 Hello and welcome to the session. In this session we discussed the following question which says the nth term of NAP is 7-4n, find its common difference. Let's move on to the solution for this question. Let the nth term of an AP be equal to An and from the question we have that An is equal to 7-4n then we have the common difference that we usually denote by D is equal to An that is the nth term minus An-1 that is N-1 Now as we have that An that is the nth term is 7-4n so An-1 that is N-1 would be equal to 7-4n to N-1 which would be equal to 11-4n Thus we have the common difference D is equal to An that is 7-4n minus An-1 that is 11-4n So this is equal to 7-4n-11 plus 4n Now this minus 4n plus 4n gets cancelled and we are left with 7-11 which is equal to minus 4 So we get the common difference D is equal to minus 4 Hence our final answer is common difference is equal to minus 4 So this completes the session hope you have understood the solution of this question