Question

4. Qual o valor da expressão (12/5):(1 + 2/7) =​

Answer 1

$\cfrac{12}{5} : (1 + \cfrac{2}{7}) \\\\= \cfrac{12}{5} : (\cfrac{7}{7} + \cfrac{2}{7}) \\\\= \cfrac{12}{5} : \cfrac{7 + 2}{7}\\\\= \cfrac{12}{5} : \cfrac{9}{7}\\\\= \cfrac{12}{5} \cdot \cfrac{7}{9}\\\\= \cfrac{12 \cdot 7}{5 \cdot 9} \\\\= \cfrac{3 \cdot 4 \cdot 7}{5 \cdot 3 \cdot 3}\\\\= \cfrac{4 \cdot 7}{5\cdot 3}\\\\= \cfrac{28}{15}$

$\boxed{\cfrac{12}{5} : (1 + \cfrac{2}{7}) = \cfrac{28}{15} }$