Răspuns:
Explicație pas cu pas:
205-55:{28-23:[13-6x(4-2xD)]}=194
55:{28-23:[13-6x(4-2xD)]} = 205 - 194 = 11
28-23:[13-6x(4-2xD)] = 55 : 11 = 5
23:[13-6x(4-2xD)] = 28 - 5 = 23
13-6x(4-2xD) = 23 : 23 = 1
6x(4-2xD) = 13 - 1 = 12
4-2xD = 12 : 6 = 2
2xD = 4 - 2 = 2
D = 2 : 2 = 1
