Đáp án:
Giải thích các bước giải:
Bài 1:
a)$\frac{-13}{240}$và$\frac{-7}{80}$
$\frac{-13}{240}$ Giữ nguyên
$\frac{-7}{80}$=và$\frac{-7.3}{80.3}$=$\frac{-21}{240}$
b)$\frac{3}{-10}$và$\frac{-5}{21}$
$\frac{3}{-10}$=$\frac{-3}{10}$=$\frac{-3.21}{10.21}$=$\frac{-63}{210}$
$\frac{-5}{21}$=$\frac{-5.10}{21.10}$=$\frac{-50}{210}$
c)$\frac{7}{60}$,$\frac{3}{-40}$và$\frac{-11}{30}$
$\frac{7}{600}$=$\frac{7.2}{60.20}$=$\frac{14}{120}$
$\frac{3}{-40}$=$\frac{-3}{40}$=$\frac{-3.3}{40.3}$và$\frac{-9}{120}$
$\frac{-11}{30}$=$\frac{-11.4}{30.4}$=$\frac{-44}{120}$
d)$\frac{5}{21}$,$\frac{-3}{28}$và$\frac{-45}{108}$
$\frac{5}{21}$=$\frac{5.36}{21.36}$=$\frac{180}{756}$
$\frac{-3}{28}$=$\frac{-3.27}{28.27}$=$\frac{-81}{756}$
$\frac{-45}{108}$=$\frac{-45.7}{108}$=$\frac{-315}{756}$