K=-3 because 1st you distribute 2 to 5 and -6 and you will get -4k+10k-12=-3k-39 then you would add like terms and add -4k+10k and get 6k-12=-3k-39 then you add 3k on both sides and get 9k-12=-39 then add 12 on both sides and get 9k=-27, divide 9 on both sides and your final answer would be -3=k
