 Hello and welcome to the session. The given question says, find the sum of the first 25 terms of an AP whose nth term is given by dn is equal to 2 minus 3n. Let's start with the solution. Here we are given that the nth term of an AP is 2 minus 3n. So when n is equal to 1, the first term is 2 minus 3 into 1 which is equal to minus 1 and when n is equal to 25, then the 25th term is given by 2 minus 3 into 25 which is equal to 2 minus 75 which is equal to minus 73. Therefore, the first term of the AP is minus 1 and the 25th term is minus 73. Now if t1, t2, t3 up to tn is an AP, then the sum of first n terms denoted by sn is given by n by 2 into t1 plus the nth term. So here the sum of 25 terms that is denoted by s25 is equal to 25 divided by 2 into inside the bracket first term plus the 25th term and this is equal to 25 divided by 2 into minus 74 which is equal to 25 into minus 37 and on multiplying it we get minus 925. Hence our answer is the sum of first 25 terms is minus 925 and this completes the session. Bye and take care.