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j) \(\frac{8}{3}.\frac{2}{5}.\frac{3}{8}.10.\frac{19}{92}=\left(\frac{8}{3}.\frac{3}{8}\right).\left(\frac{2}{5}.10\right).\frac{19}{92}=1.4.\frac{19}{92}\)
\(=\frac{19}{23}\)
k)\(\frac{-5}{7}.\frac{2}{11}.\frac{-13}{17}.\frac{19}{12}.\frac{17}{13}=\left(\frac{2}{11}.\frac{19}{12}\right).\left(\frac{-13}{17}.\frac{17}{13}\right).\frac{-5}{7}\)
\(=\frac{-19}{66}.\frac{-5}{7}=\frac{95}{462}\)
l)\(\frac{12}{19}.\frac{7}{15}.\frac{-13}{17}.\frac{19}{12}.\frac{17}{13}=\left(\frac{12}{19}.\frac{19}{12}\right).\left(\frac{-13}{17}.\frac{17}{13}\right).\frac{7}{15}\)
\(=\frac{-7}{15}\)
cậu tham khảo trên này ạ, nếu đúng cho mk 1 t.i.c.k ạ, thank nhiều
\(3\frac{14}{19}+\frac{13}{17}+\frac{35}{43}+6\frac{5}{19}+\frac{8}{43}\)
\(\left(3\frac{14}{19}+6\frac{5}{19}\right)+\left(\frac{35}{43}+\frac{8}{43}\right)+\frac{13}{17}\)
\(10+1+\frac{13}{17}=11+\frac{13}{17}=11\frac{13}{17}\)
\(11\frac{3}{13}-\left(2\frac{4}{7}+5\frac{3}{13}\right)\)
\(=11\frac{3}{13}-2\frac{4}{7}-5\frac{3}{13}\)
\(=\left(11\frac{3}{13}-5\frac{3}{13}\right)-2\frac{4}{7}\)
\(=6-2-\frac{4}{7}\)
\(=4-\frac{4}{7}=3\frac{3}{7}\)
\(a)15\frac{3}{13}-\left(3\frac{4}{7}+8\frac{3}{13}\right)\)
\(=15\frac{3}{13}-3\frac{4}{7}-8\frac{3}{13}\)
\(=15\frac{3}{13}-8\frac{3}{13}-3\frac{4}{7}\)
\(=7-3\frac{4}{7}\)
\(=6\frac{7}{7}-3\frac{4}{7}=3\frac{3}{7}\)
\(b)\left(7\frac{4}{9}+4\frac{7}{11}\right)-3\frac{4}{9}\)
\(=7\frac{4}{9}-4\frac{7}{11}-3\frac{4}{9}\)
\(=7\frac{4}{9}-3\frac{4}{9}-4\frac{7}{11}\)
\(=4-4\frac{7}{11}=\frac{7}{11}\)
a, \(\frac{34}{13}-\frac{19}{28}-\frac{3}{31}=>\left(\frac{34}{13}-\frac{3}{31}\right)-\frac{19}{28}\)
= \(1-\frac{19}{28}=\frac{9}{28}\)
b, \(b,\frac{7}{3}-\left(\frac{11}{5}+\frac{4}{5}\right)\)
= \(\frac{7}{3}-3=>\frac{7}{3}-\frac{9}{3}=\frac{-2}{3}\)
c, \(\frac{18}{13}+\frac{55}{46}-\frac{5}{13}=\left(\frac{18}{13}-\frac{5}{13}\right)+\frac{55}{46}\)
= \(1+\frac{55}{46}=\frac{46}{46}+\frac{55}{46}=\frac{101}{46}\)
Bài này mình sẽ giảng thôi, tại nó cũng khá dễ ạ
Câu A: Bạn phá ngoặc, đổi dấu + trong ngoặc thành -, lấy cái thứ nhất - cái thứ 3 , ra kết quả thì - cái thứ 2 (Bạn tự quy đồng ...)
Câu B: Bạn lấy 5/9 làm thừa số chung và cho 7/13 + 9/13 - 3/13 vào trong ngoặc, tính ra được cái trong ngoặc rồi lấy 5/9 x với kết quả vừa tính được
a) \(\left(\frac{1}{4}+-\frac{5}{13}\right)+\left(\frac{2}{11}+-\frac{8}{13}+\frac{3}{4}\right)\)
\(=\frac{2}{11}+\left(\frac{1}{4}+\frac{3}{4}\right)+\left(-\frac{5}{13}+-\frac{8}{13}\right)\)
\(=\frac{2}{11}+1+\left(-1\right)\)
\(=\frac{2}{11}+0\)
\(=\frac{2}{11}\)
b) \(\left(\frac{21}{31}+-\frac{16}{7}\right)+\left(\frac{44}{53}+\frac{10}{31}\right)+\frac{9}{53}\)
\(=-\frac{16}{7}+\left(\frac{21}{31}+\frac{10}{31}\right)+\left(\frac{44}{53}+\frac{9}{53}\right)\)
\(=-\frac{16}{7}+1+1\)
\(=-\frac{16}{7}+2\)
=\(-\frac{2}{7}\)
c) \(\frac{\frac{9}{45}-\frac{4}{13}-\frac{1}{3}}{\frac{3}{13}-\frac{1}{15}+\frac{2}{3}}\)
\(=-\frac{43}{81}\)
a) \(\frac{2}{5}+\left(\frac{3}{11}+\frac{-2}{5}\right)\)
\(=\frac{2}{5}+\frac{3}{11}+\frac{-2}{5}\)
\(=\left(\frac{2}{5}+\frac{-2}{5}\right)+\frac{3}{11}\)
\(=0+\frac{3}{11}\)
\(=\frac{3}{11}\)
b) \(\frac{-5}{7}\cdot\frac{4}{13}+\frac{-5}{7}\cdot\frac{9}{13}+\frac{-2}{7}\)
\(=\frac{-5}{7}\left(\frac{4}{13}+\frac{9}{13}\right)+\frac{-2}{7}\)
\(=\frac{-5}{7}\cdot1+\frac{-2}{7}\)
\(=\frac{-5}{7}+\frac{-2}{7}\)
\(=-1\)
=))
a) 2/5 + (3/11 -2/5 ) = 2/5 - 2/5 + 3/11 = 3/11
b) -5/7*4/13+(-5/7 ) *9/13 + (-2/7) =-5/7( 4/13 + 9/13 ) -2/7 = -1
Lời giải:
$\frac{11}{13}A=\frac{11}{3.14}+\frac{11}{14.25}+\frac{11}{25.36}+...+\frac{11}{58.69}$
$=\frac{14-3}{3.14}+\frac{25-14}{14.25}+\frac{36-25}{25.36}+...+\frac{69-58}{58.69}$
$=\frac{1}{3}-\frac{1}{14}+\frac{1}{14}-\frac{1}{25}+\frac{1}{25}-\frac{1}{36}+...+\frac{1}{58}-\frac{1}{69}$
$=\frac{1}{3}-\frac{1}{69}$
$=\frac{22}{69}$
$\Rightarrow A=\frac{22}{69}:\frac{11}{13}=\frac{26}{69}$
Lời giải:
$\frac{7}{3}B = \frac{7}{18.25}+\frac{7}{25.32}+...+\frac{7}{53.60}$
$=\frac{25-18}{18.25}+\frac{32-25}{25.32}+...+\frac{60-53}{53.60}$
$=\frac{1}{18}-\frac{1}{25}+\frac{1}{25}-\frac{1}{32}+...+\frac{1}{53}-\frac{1}{60}$
$=\frac{1}{18}-\frac{1}{60}$
$=\frac{7}{180}$
$\Rightarrow B=\frac{7}{180}:\frac{7}{3}$
$\Rightarrow B=\frac{1}{60}$