Expand the expression and combine like terms. 5(10k + 1) + 2(2 + 8k)

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!

N- 3 is the answer