3. 100 = 10²
10² * 10²ˣ =10³ˣ
10²⁺²ˣ = 10³ˣ
2+2x = 3x
2x-3x = -2
-x = -2
x = 2
4. fie ab numar natural unde b este sigur o cifra para folosind multimea {0,1,2,3,4}
ab ={10,12,14 , 20, 24, 30, 32,34, 40, 42}