I am having trouble understanding a step in the following problem.
2(2+2k) + (1+k)
The steps in the text are as follows:
2(2+k) + (1+k) = (2*2*1)(1+k) = 5(1+k)
I do not understand how you get (2*2*1) from 2(2+2k)
Thank you for any help in advance.