cineva care stie cum se fac?

1)
OPUSUL:
[tex] \huge - ( - \frac{7}{3} ) = \frac{7}{3} [/tex]
INVERSUL:
[tex] \huge - \frac{3}{7} [/tex]
MODULUL:
[tex] \huge| - \frac{7}{3} | = \frac{7}{3} [/tex]
2)
a) 2,1
b) 12/99 simplificam prin 3 = 4/33
c) 126-12/90 = 114/90 simplificam prin 2 = 57/45