Question

determinati numerele naturale ab astfel incat ab-ba sa fie cub perfect
VA ROG!!!!

Answer 1

ab-ba=10a+b-10b-a=9a-9b=9(a-b)=3²(a-b)

3²(a-b) cub perfect =>  a-b=3

(a, b)∈{(4, 1), (5, 2), (6, 3), (7, 4), (8, 5), (9, 6)}

ab∈{41, 52, 63, 74, 85, 96}