Câu hỏi của Kiet Vo

Question

1/$4.\left(\dfrac{-1}{2}\right)^{^{ }3}+\dfrac{1}{2}:5$

2/$17\dfrac{1}{5}:\left(\dfrac{-5}{7}\right)-2\dfrac{1}{5}.\left(\dfrac{-7}{5}\right)$

Help me

Trần Phạm Nọc Tuyết · Accepted Answer

1/$\dfrac{-2}{5}$

2/-21Câu trả lời: 1/$\dfrac{-2}{5}$

2/-21

Phạm Ngân Hà · Answer

1/ $4\left(\dfrac{-1}{2}\right)^3+\dfrac{1}{2}:5$

$=4.\dfrac{-1}{8}+\dfrac{1}{2}.\dfrac{1}{5}$

$=\dfrac{-1}{2}+\dfrac{1}{10}$

$=\dfrac{-5}{10}+\dfrac{1}{10}$

$=\dfrac{-4}{10}$

$=\dfrac{-2}{5}$

2/ $17\dfrac{1}{5}:\left(-\dfrac{5}{7}\right)-2\dfrac{1}{5}.\left(-\dfrac{7}{5}\right)$

$=\dfrac{86}{5}.\left(\dfrac{-7}{5}\right)-\dfrac{11}{5}.\left(\dfrac{-7}{5}\right)$

$=\dfrac{-7}{5}.\left(\dfrac{86}{5}-\dfrac{11}{5}\right)$

$=\dfrac{-7}{5}.15$

$=-21$Câu trả lời: 1/ $4\left(\dfrac{-1}{2}\right)^3+\dfrac{1}{2}:5$