Question

Aflati numerele ab care impartite la 36 dau restul patrat perfect

Answer 1

ab:36=x la patrat
ab=78,81,

Answer 2

ab  = 36c + r    c∈{0,1,2}     r < 36  (36·3 = 108 are 3 cifre) 
ptr. c=0  r ∈ {1,4,9,16,25} ab = 0·36 +r ⇒ ab ∈ {16,25}
ptr. c= 1 " " " " "" "  "" " " "  ab =1·36 +r ⇒ ab ∈ {37, 40, 45, 52, 61}
ptr. c = 2 " " " " " " " " " """  ab = 2·36·+r ⇒ ab ∈ {73,76,81,88,97}