1 = 10
2 = 5
3 = 2,5
4 = 1,25
5 = ?
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Mk ko ghi lại đề nhé
1 = \(350-4.19+4.7\)
\(=350-4.\left(19+7\right)\)
\(=350+4.26\)
\(=350-104=246\)
2 Câu này mình vẫn chưa hiểu là bạn ghi 27 3/5 tức là 27.3/5 hay 27\(\dfrac{3}{5}\)nên mk bỏ qua nhé
3 Cái đoạn 1 1/3 y chang câu 2
4 \(=\dfrac{2}{3}+\dfrac{1}{3}.\dfrac{7}{18}.\dfrac{12}{7}\)
\(=\dfrac{2}{3}+\dfrac{7}{54}.\dfrac{12}{7}\)
\(=\dfrac{2}{3}+\dfrac{2}{9}=\dfrac{8}{9}\)
5 \(=2^2+10^2-\left[9.\left(112:8\right)-11\right].1\)
\(=4+100-\left(9.14-11\right)\)
\(=104-115\)\(=-11\)
6 Đoạn 6 3/5 y chang 2,3
7 \(=\left(\dfrac{2}{3}-1\right)+\left(\dfrac{2}{7}-\dfrac{3}{7}\right)-\left(\dfrac{1}{14}-\dfrac{3}{28}\right)\)
\(=\dfrac{-1}{3}+\dfrac{-1}{7}-\dfrac{-1}{28}\)
\(=\dfrac{-196}{588}+\dfrac{-84}{588}-\dfrac{-21}{588}\)\(=\dfrac{259}{588}\)
Làm tạm tạm thôi xl vì có 3 câu ko hiểu
mik cách ra nghĩa là ghi 27, 3 phần 5 (mấy câu khác cx zị)hog phải nhân nha
a, \(\left(3\dfrac{1}{3}+2,5\right):\left(3\dfrac{1}{6}-4\dfrac{1}{5}\right)-\dfrac{11}{31}\)
\(=\left(\dfrac{10}{3}+2,5\right):\left(\dfrac{19}{6}-\dfrac{21}{5}\right)-\dfrac{11}{31}\)
\(=\dfrac{35}{6}:\dfrac{-31}{30}-\dfrac{11}{31}=-\dfrac{175}{31}-\dfrac{11}{31}=-6\)
b,Sửa đề: \(\dfrac{\dfrac{3}{21}-\dfrac{12}{47}+\dfrac{27}{53}}{\dfrac{4}{21}-\dfrac{16}{47}+\dfrac{36}{53}}==\dfrac{\dfrac{1}{3}.\left(\dfrac{1}{21}-\dfrac{4}{47}+\dfrac{9}{53}\right)}{\dfrac{1}{4}.\left(\dfrac{1}{21}-\dfrac{4}{47}+\dfrac{9}{53}\right)}\)
\(=\dfrac{\dfrac{1}{3}}{\dfrac{1}{4}}=\dfrac{4}{3}\)
Chúc bạn học tốt!!!
Answer:
a. \(M_X=2.16=32đvc\)
Đặt \(\hept{\begin{cases}x\left(mol\right)=n_{CO_2}\\y\left(mol\right)=n_{CO}\end{cases}}\)
\(m_X=44x+28y\left(g\right)\)
\(n_X=x+y\left(mol\right)\)
\(M_X=\frac{m_X}{n_X}=32\)
\(\Rightarrow\frac{44x+28y}{x+y}=32g/mol\)
\(\Rightarrow12x=4y\)
\(\Rightarrow\frac{x}{y}=\frac{4}{12}=\frac{1}{3}\)
\(\Rightarrow n_{CO_2}:n_{CO}=1:3\)
b. \(M_Y=1,255.29=36,395đvc\)
Đặt \(\hept{\begin{cases}x\left(mol\right)=n_{NO_2}\\y\left(mol\right)=n_{NO}\end{cases}}\)
\(m_Y=46x+30y\left(g\right)\)
\(n_Y=x+y\left(mol\right)\)
\(M_Y=\frac{m_Y}{n_Y}=36,395g/mol\)
\(\Rightarrow\frac{46x+30y}{x+y}=36,395\)
\(\Rightarrow9,605x=6,395y\)
\(\Rightarrow\frac{x}{y}=\frac{6,395}{9,065}=\frac{1279}{1813}\)
\(\Rightarrow n_{NO_2}:n_{NO}=1279:1921\)
\(\left(\frac{3}{4}+\frac{2}{11}-\frac{8}{13}\right)+\left(\frac{1}{4}-\frac{5}{13}\right)\)
\(=\frac{3}{4}+\frac{2}{11}-\frac{8}{13}+\frac{1}{4}-\frac{5}{13}\)
\(=\left(\frac{3}{4}+\frac{1}{4}\right)+\frac{2}{11}-\left(\frac{8}{13}+\frac{5}{13}\right)\)
\(=1+\frac{2}{11}-1\)
\(=\frac{2}{11}\)
\(\left(\frac{9}{53}+\frac{21}{31}\right)+\left(\frac{44}{53}-\frac{16}{7}\right)+\frac{10}{31}\)
\(=\frac{9}{53}+\frac{21}{31}+\frac{44}{53}-\frac{16}{7}+\frac{10}{31}\)
\(=\left(\frac{9}{53}+\frac{44}{53}\right)+\left(\frac{21}{31}+\frac{10}{31}\right)-\frac{16}{7}\)
\(=1+1-\frac{16}{7}\)
\(=2-\frac{16}{7}\)
\(=\frac{14}{7}-\frac{16}{7}\)
\(=\frac{-2}{7}\)
\(-\dfrac{5}{6}-\dfrac{3}{10}=-\dfrac{17}{15}\)
\(-\dfrac{1}{3}+-\dfrac{3}{4}-\dfrac{2}{5}=-\dfrac{13}{12}-\dfrac{2}{5}=-\dfrac{89}{60}\)
\(-\dfrac{2}{9}-\dfrac{11}{6}-\dfrac{7}{12}=-\dfrac{37}{18}-\dfrac{7}{12}=-\dfrac{95}{36}\)
\(\dfrac{2}{5}--\dfrac{7}{10}-\dfrac{4}{15}=\dfrac{11}{10}-\dfrac{4}{15}=\dfrac{5}{6}\)
\(#YH\)
\(#NBaoNgoc\)
\(\dfrac{1}{2}+\dfrac{2}{3}+\dfrac{3}{5}\)
\(=\dfrac{15}{30}+\dfrac{20}{30}+\dfrac{18}{30}\)
\(=\dfrac{15+20+18}{30}\)
\(=\dfrac{53}{30}\)
_________________
\(\dfrac{3}{8}+\dfrac{3}{4}+\dfrac{1}{16}\)
\(=\dfrac{12}{32}+\dfrac{24}{32}+\dfrac{2}{32}\)
\(=\dfrac{12+24+2}{32}\)
\(=\dfrac{19}{16}\)
_______________
\(\dfrac{2}{5}+\dfrac{3}{10}+\dfrac{28}{35}+\dfrac{3}{2}\)
\(=\dfrac{2}{5}+\dfrac{3}{10}+\dfrac{4}{5}+\dfrac{3}{2}\)
\(=\dfrac{4}{10}+\dfrac{3}{10}+\dfrac{8}{10}+\dfrac{15}{10}\)
\(=\dfrac{4+3+8+15}{10}\)
\(=\dfrac{30}{10}\)
\(=3\)
tổng trên có số số hạng là:
(10-0,5):0,5+1=20(số)
tổng trên là:
(10+0,5)*20:2=105
đáp số:..
phải như thế này mới đúng:
ghi đề bài
=(10+0,5)+(9,5+1)+(9+1,5)+.....+(6+5,5)
=10,5x10(số cặp)=150
5 = 2 because 2 = 5
5=0,625 nha bạn ^-^