Coroana???
27.
[tex] \frac{20}{30} = \frac{4}{6} = \frac{2}{3} [/tex]
[tex] \frac{250}{350} = \frac{25}{35} = \frac{5}{7} [/tex]
[tex] \frac{2 \times 7 \times 3}{3 \times 7 \times 11} = \frac{2 \times 21}{3 \times 77} = \frac{42}{231} = \frac{6}{33} = \frac{2}{11} [/tex]
[tex] \frac{ {2}^{3} }{ {2}^{5} } = \frac{8}{32} = \frac{1}{4} [/tex]
28.
a)x=2
y=4
b)x=9
y=5
