Can someone please explain this to me, I know the answer but can not figure out how to get it?

Question

(15)(.8)^4(1-.8)^2+(6)(.8)^5(1-.8)^1+(1)(.8)^6(1-.8)^0

Answer 1

I just entered your calculations into the Google window and look what it gave me

http://www.google.ca/search?hl=en&source=hp&q=%2815%29%28.8%29%5E4%281-.8%29%5E2%2B%286%29%28.8%29%5E5%281-.8%29%5E1%2B%281%29%28.8%29%5E6%281-.8%29%5E0&aq=f&aqi=&aql=&oq=&gs_rfai=

Answer 2

I knew the answer, I don't understand how they got the answer I have tried a million times now.