Question

Find the missing term of terms each arithmetic sequence 29_-31

Answer 1

$If\ a_1;\ a_2;\ a_3\ are\ therms\ of\ an\ arythmetic\ sequence,\ then\\\\a_1+a_3=2a_2\\-----------------\\\\29;\ x;\ -31\\\\2x=29+(-31)\\2x=29-31\\2x=-2\ \ \ \ |divide\ both\ sides\ by\ 2\\\boxed{x=-1}$