$\frac{-12}{25}$ : $\frac{7}{8}$ + $\frac{-9}{8}$ . $\frac{12}{25}$ - $\frac{1}{25}$
= $\frac{-12}{25}$ . $\frac{8}{7}$ + $\frac{9}{8}$ . $\frac{-12}{25}$ - $\frac{1}{25}$
= $\frac{-12}{25}$ . ( $\frac{8}{7}$ + $\frac{9}{8}$ ) - $\frac{1}{25}$
= $\frac{-12}{25}$ . ( $\frac{64}{56}$ + $\frac{63}{56}$ ) - $\frac{1}{25}$
= $\frac{12}{25}$ . $\frac{127}{56}$ - $\frac{1}{25}$
= $\frac{254}{575}$ - $\frac{1}{25}$
= $\frac{254}{575}$ - $\frac{23}{575}$
= $\frac{231}{575}$
HỌC TỐT NHA !
#NOCOPY
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