Question

determina numarul natural natural x,astfel incat 18
--------- E N
2x+1

Answer 1

18/2x+1∈N⇒2x+1∈D18
D18∈{1,2,3,6,9,18}

1. 2x+1=1
    2x=1-1
    2x=0
    x=0:2=0

2.  2x+1=3
     2x=3-1
     2x=2
     x=2:2=1

3.  2x+1=9
     2x=9-1
     2x=8
     x=8:2=4

Answer 2

[tex] \frac{18}{2x+1}apartine~lui~N\\ 18~trebuie~sa~se~imparta~exact~la~2x+1\\ 18,se~imparte~exact~la:1,2,3,6,9,deci~2x+1=1,2,3,6,9.\\ =\ \textgreater \ 2x+1=1=\ \textgreater \ 2x=0=\ \textgreater \ x=0\\ 2x+1=2=\ \textgreater \ 2x=1=\ \textgreater \ x=0,5\\ 2x+1=3=2x=2=\ \textgreater \ x=1\\ 2x+1=6=\ \textgreater \ 2x=5=\ \textgreater \ x=2,5\\ 2x+1=9=\ \textgreater \ 2x=8=\ \textgreater \ x=4\\\\ Proba:2*0+1=1=\ \textgreater \ 18:1=18(corect)\\ 2*0,5+1=1+1=2=\ \textgreater \ 18:2=9(corect)\\ 2*1+1=3=\ \textgreater \ 18:3=6(corect)\\ 2*2,5+1=5+1=6=\ \textgreater \ 18:6=3(corect)\\ 2*4+1=9=\ \textgreater \ 18:9=2(corect)\\ [/tex]