Question

for what values of k the number x,3x+k, 3x+6 are three congestive terms of an ap

Answer 1

lets consider x as1
then, the no. will be
1, 3+k,3+6=9
now mean of 1 and 9 would be 3+k as they are in ap
so, 1+9/2=3+k
10/2=3+k
5=3+k
k=5-3
therefore, k = 2