9^7 = 9^6 × 9 = (9^2)^3 × (1^3 + 2^3) =
= (81 × 1)^3 + (81 × 2)^3 =
= 81^3 + 162^3
___________
28^28 = 28^27 × 28 =
= (28^9)^3 × (1^3 + 3^3) =
= (28^9 × 1)^3 + (28^9 × 3)^3 =
= (28^9)^3 + (28^9 × 3)^3
____________________
35^19 = 35^18 × 35 = (35^6)^3 × (2^3 + 3^3) =
= (35^6 × 2) + (35^6 × 3)^3
_______________________