x= 7¹⁸⁰ +1 +4²⁰⁰ + 8²⁰¹
1 la orice putere da 1
7¹=(.....7)
7²=(.....9)
7³=(.....3)
7⁴=(.....1)
7⁵=(.....7)
se repeta din 4 in 4 180:4=45 rest 0 => 7¹⁸⁰=(......1)
4¹=(.....4)
4²=(.....6)
4³=(.....4)
se repeta din 2 in 2 200:2=100 rest 0 =>4²⁰⁰=(.....6)
8¹=(.....8)
8²=(.....4)
8³=(.....2)
8⁴=(.....6)
8⁵=(.....8)
se repeta din 4 in 4 201:4=50 rest 1 => 8²⁰¹= (......8)
x=(......1)+1+(......6)+(.......8)=
=(......7)+(.......9)= (.......6) : 2 (trebuiau 3 puncte)
