\(\frac{x}{56}=\frac{21}{24}\)
\(\frac{16}{15}\cdot\frac{-5}{14}\cdot\frac{54}{24}\cdot\frac{56}{21}\)
\(\frac{-3}{5}+\frac{28}{5}\left(\frac{43}{56}+\frac{5}{24}-\frac{21}{63}\right)\)
Tìm các tích sau :
a/ \(\frac{16}{15}\times\frac{-5}{14}\times\frac{64}{24}\times\frac{56}{21}\)
b/ \(\frac{7}{3}\cdot\frac{-5}{2}\cdot\frac{15}{21}\cdot\frac{4}{-5}\)
tìm các tích sau: a) \(\frac{16}{15}.\frac{-5}{14}.\frac{54}{24}.\frac{56}{21}\) b) \(\frac{7}{3}.\frac{-5}{2}.\frac{15}{21}.\frac{4}{-5}\)
a, \(-\frac{16}{7}\) b, \(\frac{10}{3}\)
quy đồng mẫu số :
\(\frac{-3}{16}\); \(\frac{5}{24}\); \(\frac{-21}{56}\)
\(\frac{56}{x}=\frac{14}{21}\)
Tìm x
\(\frac{56}{x}=\frac{14}{21}=\frac{2}{3}\)
\(\Leftrightarrow x=\frac{56.3}{2}=84\)
\(\frac{56}{x}=\frac{14}{21}\)
\(\Leftrightarrow x=84\)
Vậy x=84
56 . 21 = 14 . x
=> 1176 : 14 . x
=> x = 84
a) \(\left(\frac{9}{10}-\frac{15}{16}\right).\left(\frac{5}{12}-\frac{11}{15}-\frac{7}{20}\right)\)
B) \(\frac{-3}{5}+\frac{28}{5}.\left(\frac{43}{56}+\frac{5}{24}-\frac{21}{63}\right)\)
thực hiện phép tính
1. Tìm x thuộc Z biết:
a,\(\frac{-5}{6}.\frac{120}{25}< x< \frac{-7}{15}.\frac{9}{14}\)
b,\(\left(\frac{-5}{3}\right)^3< x< \frac{-24}{35}.\frac{-5}{6}\)
2. Thực hiện phép tính:
a,\(\left(\frac{9}{10}-\frac{15}{16}\right).\left(\frac{5}{12}-\frac{11}{15}-\frac{7}{20}\right)\)
b,\(\frac{-3}{5}+\frac{28}{5}.\left(\frac{43}{56}+\frac{5}{24}-\frac{21}{63}\right)\)
AI GIÚP MIK VỚI,MIK DÂNG CẦN GẤP,SÁNG MAI MIK PHẢI NỘP CHO CÔ RỒI,GIÚP MIK NHA
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)
\(\left(\frac{9}{10}-\frac{15}{16}\right).\left(\frac{5}{12}-\frac{11}{15}-\frac{7}{20}\right)\)
\(=\left(\frac{72}{80}-\frac{75}{80}\right).\left(\frac{25}{60}-\frac{44}{60}-\frac{21}{60}\right)\)
\(=\frac{-3}{80}.\frac{-40}{60}\)
\(=\frac{-1}{-2}.\frac{-1}{-20}\)
\(=\frac{1}{40}\)
Quy đồng mẫu các phân số sau:
\(\frac{-3}{10}\),\(\frac{5}{24}\),\(\frac{-21}{56}\)
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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