Quy đồng mẫu các phân số:
a. \(\frac{{ - 5}}{5},\frac{8}{7}\) b.\(3,\frac{{ - 3}}{5},\frac{{ - 5}}{6}\) c.\(\frac{{ - 9}}{7},\frac{{ - 19}}{{15}}, - 1\)
Câu a:
\(\frac{{ - 5}}{5} = - 1\)nên \(\frac{{ - 5}}{5} = \frac{{ - 7}}{7}\)
Câu b:
\(3 = \frac{3}{1} = \frac{{3.30}}{{1.30}} = \frac{{90}}{{30}},\frac{{ - 3}}{5} = \frac{{ - 3.6}}{{5.6}} = \frac{{ - 18}}{{30}},\frac{{ - 5}}{6} = \frac{{ - 5.5}}{{6.5}} = \frac{{ - 25}}{{30}}\)
Câu c:
\(\frac{{ - 9}}{7} = \frac{{ - 9.15}}{{7.15}} = \frac{{ - 135}}{{105}};\frac{{ - 19}}{{15}} = \frac{{ - 19.7}}{{15.7}} = \frac{{ - 133}}{{105}}, - 1 = \frac{{ - 105}}{{105}}\)
-- Mod Toán 6
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