Cách làm cho bạn:
Ta tính:
$A = \frac{13}{50} . (−15,5)−\frac{13}{50} . 84\frac{1}{2}$;
= $ \frac{13}{50} . (−15,5 - 84,5)−\frac{13}{50}$
= $ \frac{13}{50} . (-100) = -26$
$B=\frac{(−0,7)^{2} . (−0,5)^{3}}{(\frac{−7}{3})^{3} . (\frac{3}{2})^{4} . (−1)^{5}}$
= $\frac{0,49 . (−125)}{\frac{−343}{27} . \frac{81}{16} . (−1)}$
=$ \frac{−61,25}{\frac{1029}{16}}$=
= $\frac{−245}{4} . \frac{16}{1029}$
=$\frac{−20}{21}$.
Vậy bạn An tính đúng.
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