Question

PLEASEEEE I NEED HELP!!!! Find k in the following arithmetic sequence: 4k-k^2, 3k, k

Answer 1

 3k - (k-2) = (k-2) - (k+7) 3k = (k-2) - (k+7) + (k-2) 3k = 2(k-2) - (k+7) 3k = 2k - 4 - k - 7 3k = k - 11 2k = -11 
k = -5.5