5a+25b+125c+625d = 970 : 5
a + 5b + 25c + 125d = 194
d = 1 => a + 5b + 25c + 125 = 194 => a + 5b + 25c = 69
c = 1 => a + 5b = 44
b = 1 => a = 39
b = 2 => a = 34
b = 3 => a = 29
b = 4 => a = 24
b = 5 => a = 19
b = 6 => a = 14
b = 7 => a = 9
b = 8 => a = 4
c = 2 => a + 5b + 50 = 69 => a + 5b = 19
b = 1 => a = 14
b = 2 => a = 9
b = 3 => a = 4
Acestea sunt toate solutiile.
=> (a,b,c,d) = { (39,1,1,1); (34,2,1,1); (29,3,1,1); (24,4,1,1); (19,5,1,1);
(14,6,1,1); (9,7,1,1); (4,1,1,1); (14,1,2,1); (9,2,2,1); (4,3,2,1) }
