[tex]\frac{2}{10}/ (\frac{42}{90}+ \frac{9}{20}-1 \frac{15}{90})+\frac{8}{10}=\frac{2}{10}/( -\frac{210}{180}+ \frac{84}{180}+ \frac{81}{180})+\frac{8}{10}=\frac{2}{10}/ \frac{45}{180}+\frac{8}{10}.[/tex]
Tu in paranteza amplifici prin 2 si 9 ca la numitor sa fie 180
[tex]- \frac{2}{10}* \frac{180}{45}= \frac{36}{45}= \frac{4}{5} [/tex]
Amplifici 5 cu doi ca la numitor sa fie 10
[tex] \frac{8}{10}+ \frac{8}{10}= \frac{16}{10}= \frac{8}{5} =1 \frac{3}{5} [/tex]
