Question

0,4 <3n+2/20<7/10 n€N cu propietate

Answer 1

0,4<3n+$\dfrac{2}{20}$<$\dfrac{7}{10}$

$\dfrac{2}{5}$<3n+$\dfrac{1}{10}$<$\dfrac{7}{10}$

$\dfrac{2}{5}$-$\dfrac{1}{10}$<3n<$\dfrac{7}{10}$-$\dfrac{1}{10}$

$\dfrac{3}{10}$<3n<$\dfrac{6}{10}$

$\dfrac{3}{10}$·$\dfrac{1}{3}$<n<$\dfrac{6}{20}$·$\dfrac{1}{3}$

$\dfrac{1}{10}$<n< $\dfrac{1}{10}$