[tex]\it0,8 x + 2,97 \ \textgreater \ 1,5^2\cdot3,8 |_{\cdot 100} \Rightarrow 80x+297 \ \textgreater \ 2,25\cdot380
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\Rightarrow \it 80x +297 \ \textgreater \ 855 \Rightarrow 80x \ \textgreater \ 855-297 \Rightarrow 80x \ \textgreater \ 558
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\Rightarrow\it x\ \textgreater \ 558:80 \Rightarrow x\ \textgreater \ \dfrac{\ \ 558^{(2}}{80} \Rightarrow x\ \textgreater \ \dfrac{^{25)}279}{\ \ 40}
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\Rightarrow \it x\ \textgreater \ \dfrac{6975}{1000} \Rightarrow x \ \textgreater \ 6, 975\ \ .[/tex]
Deoarece x este număr natural, vom obţine :
x ∈ {7, 8, 9, ...} sau x ∈ ℕ - {0, 1, 2, 3, 4, 5, 6}