Solve for k.

18 = 10 + 2k

k =

18 = 10 + 2k

move 10 to the other side

sign changes from + 10 to - 10

18-10=10-10+2k

18-10 = 2k

8 = 2k

divide by 2 to get k by itself

8/2 = 2k/2

Cross out 2 and 2, divide by 2 and then becomes 1*1*k = k

k=8/2

Answer: k = 4