412:4 + {19+2[216-5(ab+1)]} x10 = 2013
{19+2[216-5(ab+1)]} x10 = 2013-103 = 1910
{19+2[216-5(ab+1)]}= 1910:10 = 191
{19+2[216-5(ab+1)]} = 191
2[216-5(ab+1)] = 191-19 = 172
432 -10(ab+1) = 172
10(ab+1) = 432-172
10(ab+1) = 260
ab+1=26 => ab=25
vom avea perechile de numere naturale:
(1 si 25) ,(5 si 5), ( 25 si 1)
