Question

Determinati, in fiecare caz, numerele naturale x stiind ca:
a) (2*x+1)|7,
b)(3*x+1)|16,
c) 30 divizibl (6*x+5),
d) 35 divizibil (2*x+1)
URGENTTT... VA ROGGG. DAU COROANA!!! MULTUMESC...

Answer 1

a) 2x + 1 ∈ D7    2x+1∈{1,7} ⇒ 2x∈{0,6}    x ∈ {0,3}
b) 3x + 1 ∈D16   3x + 1 ∈ {1,2,4,8,16}  ⇒3x ∈{0,1,3,7,15}    x ∈{0,1,5}
c) 6x + 5 ∈ D30    6x+5 ∈ {1,3,5,6,10,15,30}    6x∈{0,1,5,10,25}  x∈{0}
d) 2x + 1 ∈{1,5,7,35}    2x∈{0,4,6,34}    x∈0,2,3,17}