Question

-3/7).(21/10) tem que efetuar o calculo e dps dar a resposta



















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Answer 1

Resposta:

$(\frac{-3}{7})*(\frac{21}{10})\\\\=\frac{-3}{7}\cdot \frac{21}{10}\\\\\mathrm{Aplicar\:as\:propriedades\:das\:fracoes}:\quad \frac{-a}{b}=-\frac{a}{b}\\\\\frac{-3}{7}=-\frac{3}{7}\\\\=-\frac{3}{7}\cdot \frac{21}{10}\\\\\mathrm{Aplicar\:as\:propriedades\:das\:fracoes}:\quad \frac{a}{b}\cdot \frac{c}{d}=\frac{a\:\cdot \:c}{b\:\cdot \:d}\\\\\frac{3}{7}\cdot \frac{21}{10}=\frac{3\cdot \:21}{7\cdot \:10}\\\\=-\frac{3\cdot \:21}{7\cdot \:10}\\\\\mathrm{Fatorar\:o\:numero:\:}\:21=7\cdot \:3$

$=-\frac{3\cdot \:7\cdot \:3}{7\cdot \:10}\\\\\mathrm{Eliminar\:o\:fator\:comum:}\:7\\\\=-\frac{3\cdot \:3}{10}\\\\\mathrm{Aplicar\:as\:propriedades\:dos\:expoentes}:\quad \:aa=a^2\\\\3\cdot \:3=3^2\\\\=-\frac{3^2}{10}\\\\3^2=9\\\\=-\frac{9}{10}$