Bài trên là bài tìm các tích sau

kết quả: -16/7

giải chi tiết

= 5 x [9/14]

= 45/14

a, \(-\frac{16}{7}\)                                         b, \(\frac{10}{3}\)

\(\frac{56}{x}=\frac{14}{21}=\frac{2}{3}\)

\(\Leftrightarrow x=\frac{56.3}{2}=84\)

\(\frac{56}{x}=\frac{14}{21}\)

\(\Leftrightarrow x=84\)

Vậy x=84

56 . 21 = 14 . x

=> 1176 : 14 . x

=> x = 84

1)

a)

\(\frac{-5}{6}.\frac{120}{25}< x< \frac{-7}{15}.\frac{9}{14}\)

\(\frac{-1}{1}.\frac{20}{5}< x< \frac{-1}{5}.\frac{3}{2}\)

\(\frac{-20}{5}< x< \frac{-3}{10}\)

\(\frac{-40}{10}< x< \frac{-3}{10}\)

\(\Rightarrow Z\in\left\{-4;-5;-6;-7;-8;-9;-10;...;-39\right\}\)

\(\left(\frac{-5}{3}\right)^3< x< \frac{-24}{35}.\frac{-5}{6}\)

\(\frac{25}{3}< x< \frac{-4}{7}.\frac{1}{1}\)

\(\frac{-25}{3}< x< \frac{-4}{7}\)

\(\frac{-175}{21}< x< \frac{-12}{21}\)

\(\Rightarrow Z\in\left\{-13;-14;-15;-16;...;-174\right\}\)

2)

a)

\(\left(\frac{9}{10}-\frac{15}{16}\right).\left(\frac{5}{12}-\frac{11}{15}-\frac{7}{20}\right)\)

\(=\left(\frac{72}{80}-\frac{75}{80}\right).\left(\frac{25}{60}-\frac{44}{60}-\frac{21}{60}\right)\)

\(=\frac{-3}{80}.\frac{-40}{60}\)

\(=\frac{-1}{-2}.\frac{-1}{-20}\)

\(=\frac{1}{40}\)

Ta có

\(10=2.5\)

\(24=2^3.3\)

\(56=2^3.7\)

MC:\(2^3.3.5.7=840\)

QĐ:\(-\frac{3}{10}=\frac{-252}{840};\frac{5}{24}=\frac{175}{840};\frac{-21}{56}=\frac{-315}{840}\)

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