Question

Care sunt nr-le nat. x care verifica relatia (x+2)divide(2x+7)?

Answer 1

(x+2) divide (2x+7)

(x+2) divide (2x+4)      (-)

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(x+2) divide (2x+7-2x-4)

(x+2) divide 3 => x+2 ∈ {1, 3} si x∈N

x+2=1 => x=-1, nu convine

x+2=3  => x=1