Start with the first expression, 5(10k + 1).
Multiply 10k by 5 to get 50k.
Multiply 1 by 5 to get 5.
Once expanded, it is 50k + 5.
The other section is 2(2 + 8k).
Multiply 2 by 2 to get 4.
Multiply 8k by 2 to get 16k.
Once expanded, it is 4 + 16k.
The like terms are 50k & 16k and 5 & 4.
Add them together.
Once expanded and combined, you get 66k + 9.
Hope this helps!
