if 3x+k,2x+9 and x+13 are three consecutive terms of an AP.,Find k.

=>(2x+9)-(3x+k)=(x+13)-(2x+9)

=>2x-3x+9-k=x-2x+13-9

=>-x+9-k=-x+4

=>9-k=4

=>-k=4-9

=>-k=-5

=>k=5 ans.

hope u understand