Find the sum of the first 25 terms of an AP, in which the third term is 7 and seventh term is 23

Find the sum of the first 25 terms of an AP, in which the third term i

1.	Find the sum of the first 25 terms of an AP, in which the third term is 7 and seventh term is 23
Answer» a3=a+2d=7...............ia7=a+6d=23..................iifrom i and ii- 4d=-16d=4a= -1a25=-1+96a25=95S25=25/2(2a+24d) =25(-1+48) =25x47 =1175 1175 And : 1175 1225 3725/7