9. daca AB = MN ; BC = NP atunci AC = MP = 4 cm
6 . D₅₄ = { 1 ;2 ; 3 ; 6 ; 9 ; 18; 27 ; 54 }
7. x∈N cu 2x -1 <5 ; 2x < 5 +1 ; 2x < 6 ; x <3
x∈ { 0 ; 1 ; 2 }
8 . α + β =90°
α / β = 1 /2 ; 2α = β
α + 2α = 90°
3α =90° ; α =30° ; β =60°
10 . 960 = 2⁶ · 3 · 5
64 = 2⁶
cmmdc= 2⁶
