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a: \(=\dfrac{7+12-6}{13}=1\)
b: \(=\dfrac{13}{10}\cdot\dfrac{6-26}{13}=\dfrac{-20}{10}=-2\)
c: \(=\dfrac{3}{4}\cdot2-\dfrac{5}{2}\cdot\dfrac{-4}{3}=\dfrac{3}{2}+\dfrac{20}{6}=\dfrac{3}{2}+\dfrac{10}{3}=\dfrac{29}{6}\)
d: \(=\dfrac{3}{8}\cdot\dfrac{8}{5}+\dfrac{3}{5}\cdot\dfrac{2}{7}+\dfrac{3}{5}\cdot\dfrac{5}{7}=\dfrac{3}{5}+\dfrac{3}{5}=\dfrac{6}{5}\)
cảm ơn bn, mình đặt câu hỏi, bn thườg xuyên trả lời câu hỏi của mình. Thank you very much.
2:
a: =>2/3:x=1,4-2,4=-1
=>x=-2/3
b: =>x/5=25/30-19/30=6/30=1/5
=>x=1
3:
Số học sinh giỏi là 40*1/4=10 bạn
Số học sinh khá là 30*3/5=18 bạn
Số học sinh TB là 30-18=12 bạn
1,
a, \(\left(\dfrac{-4}{3}+\dfrac{1}{3}\right).\dfrac{5}{12}\)=-\(\dfrac{5}{12}\)
b, \(\dfrac{16}{5}+\left(\dfrac{-45}{14}\right):\dfrac{3}{28}\)
=\(\dfrac{-2}{15}\)
2,
a, 2x+19=25
=>x=3
b, \(-\dfrac{2}{9}x=\dfrac{1}{3}\)
=>x=\(\dfrac{-3}{2}\)
Bài 1:
a) Ta có: \(\dfrac{-4}{3}\cdot\dfrac{5}{12}+\dfrac{1}{3}\cdot\dfrac{5}{12}\)
\(=\dfrac{5}{12}\cdot\left(\dfrac{-4}{3}+\dfrac{1}{3}\right)\)
\(=\dfrac{-5}{12}\)
b) Ta có: \(3\dfrac{1}{5}+\left(\dfrac{2}{7}-\dfrac{7}{2}\right):\dfrac{3}{28}\)
\(=\dfrac{16}{5}+\left(\dfrac{4}{14}-\dfrac{49}{14}\right):\dfrac{3}{28}\)
\(=\dfrac{16}{5}+\dfrac{-45}{14}\cdot\dfrac{28}{3}\)
\(=\dfrac{16}{5}-30=\dfrac{-134}{5}\)
a) \(x-\dfrac{5}{6}=\dfrac{1}{2}\)
\(x=\dfrac{1}{2}+\dfrac{5}{6}\)
\(x=\dfrac{4}{3}\)
vậy x = ....
b) \(3\dfrac{1}{3}x+16\dfrac{3}{4}=-13,25\)
\(\dfrac{10}{3}\)\(x+\dfrac{67}{4}=-13,25\)
\(\dfrac{10}{3}x=\left(-13,25\right)-\dfrac{67}{4}\)
\(\dfrac{10}{3}x=-30\)
\(x=\left(-30\right):\dfrac{10}{3}\)
\(x=-9\)
vậy x =...
sai mog bn thông cảm!!!
a) \(\dfrac{-4}{3}-\dfrac{2}{7}+\dfrac{4}{3}\)
\(=\left(\dfrac{-4}{3}+\dfrac{4}{3}\right)-\dfrac{2}{7}\)
\(=0-\dfrac{2}{7}=\dfrac{-2}{7}\)
b) \(\dfrac{1}{2}+\dfrac{-4}{5}-\dfrac{3}{10}\)
\(=\dfrac{5}{10}+\dfrac{-8}{10}-\dfrac{3}{10}\)
\(=\dfrac{5+\left(-8\right)-3}{10}=\dfrac{-3}{5}\)
a: \(=\dfrac{14-2+9}{32}\cdot\dfrac{4}{5}=\dfrac{21}{5}\cdot\dfrac{1}{8}=\dfrac{21}{40}\)
b: \(=10+\dfrac{2}{9}+2+\dfrac{3}{5}+6+\dfrac{2}{9}=18+\dfrac{47}{45}=\dfrac{857}{45}\)
c: \(=\dfrac{3}{10}-\dfrac{12}{5}+\dfrac{1}{10}=\dfrac{4}{10}-\dfrac{12}{5}=\dfrac{2}{5}-\dfrac{12}{5}=-2\)
d: \(=\dfrac{-25}{30}\left(\dfrac{37}{44}+\dfrac{13}{44}-\dfrac{6}{44}\right)=\dfrac{-25}{30}\cdot1=-\dfrac{5}{6}\)
D vì \(\dfrac{-4}{10}\)rút gọn cho 2 được\(\dfrac{-2}{5}\)
B Vì (-2).15 = (-6).5 nên \(\dfrac{-2}{5}\) = \(\dfrac{-6}{15}\)
Bài 1 :
\(=\dfrac{2}{11}+\dfrac{4}{11}-\dfrac{6}{11}-\dfrac{3}{8}-\dfrac{5}{8}=0-1=-1\)
Bài 2 :
\(\Rightarrow3+x=8\Leftrightarrow x=5\)
Bài 3 :
\(\Leftrightarrow x-\dfrac{5}{11}=\dfrac{5}{4}\Leftrightarrow x=\dfrac{35}{44}\)
Bài 4 :
Trong 2 ngày An đọc được số quyên phần quyên sách
\(\dfrac{1}{11}+\dfrac{8}{11}=\dfrac{9}{11}\)( quyển sách )
đs : 9/11 quyển sách
Câu 1:
a)\(6\dfrac{5}{8}-4\dfrac{1}{2}=\left(6+\dfrac{5}{8}\right)-\left(4+\dfrac{1}{2}\right)\\ =6+\dfrac{5}{8}-4-\dfrac{1}{2}\\ =\left(6-4\right)+\left(\dfrac{5}{8}-\dfrac{1}{2}\right)\\ =2+\dfrac{1}{8}\\ =2\dfrac{1}{8}\)
b) \(-2.013+1.01=-1.003\)
Câu 2:
\(\dfrac{2}{3}x+\dfrac{1}{2}=\dfrac{1}{10}\\ \dfrac{2}{3}x=\dfrac{1}{10}-\dfrac{1}{2}\\ \dfrac{2}{3}x=-\dfrac{2}{5}\\ x=-\dfrac{2}{5}:\dfrac{2}{3}\\ x=-\dfrac{2}{5}.\dfrac{3}{2}\\ x=-\dfrac{3}{5}\\ x=-0.6\)
Vậy x=-0.6
Câu 1
a) \(-\dfrac{23}{3}=-7\dfrac{2}{3}\)
b)\(123.45=12345\%\)
Mình nghĩ vậy