Question

Determinati elementele multimii : A=( x apartine Z cu proprietatea ca -5 supra 4-x apartine N )  va rog ajutati-maaaaaaaaaaaaaaaaaaaaaa

Answer 1

A={x∈Z/ $\frac{-5}{4-x}$∈N}
$\frac{-5}{4-x}$∈N⇒ [tex] \frac{-5}{4-x } [/tex]= 1 sau 5
Pentru $\frac{-5}{4-x}$=1⇒ 4-x=-5
x= 9
Pentru $\frac{-5}{4-x}$=5⇒ 20-5x=-5
-5x=-25
5x=25
x=5
a={5,9}
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