Tính nhanh:
C=\(\dfrac{1}{8}\)x\(\dfrac{3}{2}\)-\(\dfrac{1}{8}\)x\(\dfrac{1}{4}\)+\(\dfrac{3}{8}\)x\(\dfrac{5}{4}\)
\(\dfrac{3}{2}X-0,2=\dfrac{3}{5}\)
\(\dfrac{1}{3}+x=\dfrac{3}{4}\)
\(1\dfrac{1}{2}x-\dfrac{2}{5}=\dfrac{1}{4}\)
\(\dfrac{11}{8}-\dfrac{3}{8}.x=\dfrac{1}{8}\)
giúp với
\(\dfrac{3}{2}x-0,2=\dfrac{3}{5}\)
\(\dfrac{3}{2}x-\dfrac{1}{5}=\dfrac{3}{5}\)
\(\dfrac{3}{2}x=\dfrac{3}{5}+\dfrac{1}{5}\)
\(\dfrac{3}{2}x=\dfrac{4}{5}\)
\(x=\dfrac{4}{5}:\dfrac{3}{2}\)
\(x=\dfrac{4}{5}\cdot\dfrac{2}{3}\)
\(x=\dfrac{8}{15}\)
\(\dfrac{1}{3}+x=\dfrac{3}{4}\)
\(x=\dfrac{3}{4}-\dfrac{1}{3}\)
\(x=\dfrac{9}{12}-\dfrac{4}{12}\)
\(x=\dfrac{5}{12}\)
\(1\dfrac{1}{2}x-\dfrac{2}{5}=\dfrac{1}{4}\)
\(\dfrac{3}{2}x-\dfrac{2}{5}=\dfrac{1}{4}\)
\(\dfrac{3}{2}x=\dfrac{1}{4}+\dfrac{2}{5}\)
\(\dfrac{3}{2}x=\dfrac{13}{20}\)
\(x=\dfrac{13}{20}:\dfrac{3}{2}\)
\(x=\dfrac{13}{20}\cdot\dfrac{2}{3}\)
\(x=\dfrac{13}{30}\)
\(\dfrac{11}{8}-\dfrac{3}{8}\cdot x=\dfrac{1}{8}\)
\(\dfrac{3}{8}\cdot x=\dfrac{11}{8}-\dfrac{1}{8}\)
\(\dfrac{3}{8}\cdot x=\dfrac{5}{4}\)
\(x=\dfrac{5}{4}:\dfrac{3}{8}\)
\(x=\dfrac{5}{4}\cdot\dfrac{8}{3}\)
\(x=\dfrac{10}{3}\)
\(\dfrac{2}{5}\) x \(\dfrac{3}{4}-\dfrac{1}{8}\) \(= \)
\(\dfrac{4}{3}+\dfrac{1}{3}-\dfrac{1}{5}=\)
\(\dfrac{9}{20}-\dfrac{3}{5}\) x \(\dfrac{1}{4}\)\(= \)
\(\dfrac{2}{8}+\dfrac{2}{3}:\dfrac{4}{5}\)\(=\)
\(\dfrac{2}{5}\times\dfrac{3}{4}-\dfrac{1}{8}=\dfrac{1}{5}\times\dfrac{3}{2}-\dfrac{1}{8}=\dfrac{3}{10}-\dfrac{1}{8}=\dfrac{24}{80}-\dfrac{10}{80}=\dfrac{14}{80}=\dfrac{7}{40}\\ \dfrac{4}{3}+\dfrac{1}{3}-\dfrac{1}{5}=\dfrac{5}{3}-\dfrac{1}{5}=\dfrac{25}{15}-\dfrac{3}{15}=\dfrac{22}{15}\\ \dfrac{9}{20}-\dfrac{3}{5}\times\dfrac{1}{4}=\dfrac{9}{20}-\dfrac{3}{20}=\dfrac{6}{20}=\dfrac{3}{10}\\ \dfrac{2}{8}+\dfrac{2}{3}:\dfrac{4}{5}=\dfrac{2}{8}+\dfrac{2}{3}\times\dfrac{5}{4}=\dfrac{2}{8}+\dfrac{1}{3}\times\dfrac{5}{2}=\dfrac{2}{8}+\dfrac{5}{6}=\dfrac{1}{4}+\dfrac{5}{6}=\dfrac{6}{24}+\dfrac{20}{24}=\dfrac{26}{24}=\dfrac{13}{12}\)
a) \(2\dfrac{1}{2}\) - x + \(\dfrac{4}{5}\) = \(\dfrac{2}{3}\) - (\(-\dfrac{4}{7}\) )
b) \(-\dfrac{4}{7}\) - x = \(\dfrac{3}{5}\) - 2x
c) (\(\dfrac{3}{8}\) - \(\dfrac{1}{5}\) ) + (\(\dfrac{5}{8}\) - x) = \(\dfrac{1}{5}\)
\(a,2\dfrac{1}{2}-x+\dfrac{4}{5}=\dfrac{2}{3}-\left(-\dfrac{4}{7}\right)\\ \Rightarrow\dfrac{5}{2}-x+\dfrac{4}{5}=\dfrac{26}{21}\\ \Rightarrow\dfrac{5}{2}-x=\dfrac{46}{105}\\ \Rightarrow x=\dfrac{433}{210}\\ b,-\dfrac{4}{7}-x=\dfrac{3}{5}-2x\\ \Rightarrow2x-\dfrac{4}{7}-x=\dfrac{3}{5}\\ \Rightarrow2x-x=\dfrac{41}{35}\\ \Rightarrow x=\dfrac{41}{35}\\ c,\left(\dfrac{3}{8}-\dfrac{1}{5}\right)+\left(\dfrac{5}{8}-x\right)=\dfrac{1}{5}\\ \Rightarrow\dfrac{7}{40}+\dfrac{5}{8}-x=\dfrac{1}{5}\\ \Rightarrow\dfrac{4}{5}-x=\dfrac{1}{5}\\ \Rightarrow x=\dfrac{3}{5}.\)
Bài 4. Tìm x biết:
a. \(\dfrac{x}{5}=\dfrac{2}{5},\dfrac{3}{8}=\dfrac{6}{x},\dfrac{1}{9}=\dfrac{x}{27}\)
b. \(\dfrac{4}{x}=\dfrac{8}{6},\dfrac{3}{x-5}=\dfrac{-4}{x+2},\dfrac{x}{-2}=\dfrac{-8}{x}\)
a,2/5 = 2/5 ; 3/8=6/16 ; 1/9=3/27
b, 4/3=8/6 ; -1=-1 ; -4/-2=-8/4
tick cho mik nhé
a) x= 2, x= 8.(6 : 3) = 16, x= 1. (27 : 9)= 3
b) x= 6 : (8 : 4) = 3, x= -1, x= -2 . -8 = x.x => 16 = x2 => 42 = x2 => x=4
Tick cho mình đi
Tính bằng cách thuận tiện nhất:
a) 60 x (\(\dfrac{7}{12}\) + \(\dfrac{4}{15}\))
b) \(\dfrac{1}{2}\) x \(\dfrac{2}{3}\) x \(\dfrac{3}{4}\) x \(\dfrac{4}{5}\) x \(\dfrac{5}{6}\) x \(\dfrac{6}{7}\) x \(\dfrac{7}{8}\) x \(\dfrac{8}{9}\)
60x [7/12+4/15]
60x153/180
=9180/180
b 1/2x2/3x3/4x4/5x5/6x6/7x7/8x8/9=40320/4032
Tìm x biết:
1/ \(\dfrac{3}{5}-x=0,2\)
2/ \(\dfrac{x}{3}-\dfrac{1}{8}=\dfrac{5}{8}\)
3/ \(3\dfrac{1}{3}.x-6\dfrac{3}{4}=3\dfrac{1}{4}\)
1: =>x=3/5-1/5=2/5
b: =>x/3=5/8+1/8=3/4
=>x=9/4
3: =>10/3x=3+1/4+6+3/4=10
=>x=10:10/3=3
Tính :
a) 7 x \(\dfrac{3}{14}\) - \(\dfrac{1}{14}\) b) \(\dfrac{3}{2}\) + \(\dfrac{7}{4}\) x \(\dfrac{2}{5}\)
c) \(\dfrac{9}{8}\) : 3 + \(\dfrac{7}{8}\) : 3 d) 2 : \(\dfrac{3}{4}\) - \(\dfrac{5}{8}\) x \(\dfrac{4}{3}\)
`7 xx 3/14 -1/14`
`= 21/14 -1/14`
`= 20/14`
`=10/7`
__
`3/2 + 7/4 xx 2/5`
`= 3/2 + 14/20`
`= 3/2 + 7/10`
`= 15/10 +7/10`
`= 23/10`
__
`9/8 : 3 + 7/3 : 3`
`= 9/8 xx 1/3 + 7/3 xx 1/3`
`=1/3 xx ( 9/8 + 7/3)`
`= 1/3 xx 83/24`
`= 83/72`
__
`2 : 3/4 - 5/8 xx 4/3`
`= 2 xx 4/3 - 5/8 xx 4/3`
`= 4/3 xx ( 2-5/8)`
`= 4/3 xx ( 16/8 -5/8)`
`= 4/3 xx 11/8`
`= 44/24`
`=11/6`
` @ \color{Red}{sushiteam}`
ok giúp t thêm vài câu nữa đi :')
Tính hợp lý \(\dfrac{2}{11}\)-\(\dfrac{3}{8}\)+\(\dfrac{4}{11}\)-\(\dfrac{6}{11}\)-\(\dfrac{5}{8}\)
Số x thoả mãn \(\dfrac{1}{4}\)+\(\dfrac{x}{12}\)=\(\dfrac{8}{12}\)
Tìm x biết \(\dfrac{1}{2}\)-(x-\(\dfrac{5}{11}\))=\(\dfrac{-3}{4}\)
An đọc 1 quyển sách trong 3 ngày. Ngày thứ nhất An đọc đc \(\dfrac{1}{11}\) quyển sách,ngày thứ hai An đọc đc \(\dfrac{8}{11}\) quyển sách.Hỏi trong 2 ngày An đọc đc bao nhiêu phần quyển sách?
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
\(\dfrac{1}{3}+\dfrac{2}{3}=\)
\(\dfrac{4}{5}+\dfrac{5}{6}=\)
\(\dfrac{4}{5}-\dfrac{3}{5}=\)
\(\dfrac{9}{8}-\dfrac{4}{2}=\)
\(\dfrac{8}{5}x\dfrac{5}{8}=\)
\(\dfrac{6}{7}x\dfrac{4}{7}=\)
\(\dfrac{4}{5}:\dfrac{4}{5}=\)
\(\dfrac{5}{5}:\dfrac{5}{5}=\)
a,
\(\dfrac{1}{3}+\dfrac{2}{3}=\dfrac{3}{3}=1\)
\(\dfrac{4}{5}+\dfrac{5}{6}=\dfrac{24}{30}+\dfrac{25}{30}=\dfrac{49}{30}\)
\(\dfrac{4}{5}-\dfrac{3}{5}=\dfrac{1}{5}\)
\(\dfrac{8}{5}x\dfrac{5}{8}=\dfrac{1}{1}=1\)
\(\dfrac{6}{7}x\dfrac{4}{7}=\dfrac{24}{49}\)
\(\dfrac{4}{5}:\dfrac{4}{5}=\dfrac{4}{5}x\dfrac{5}{4}=\dfrac{1}{1}=1\)
\(\dfrac{5}{5}:\dfrac{5}{5}=\dfrac{5}{5}x\dfrac{5}{5}=\dfrac{1}{1}=1\)
1) \(\dfrac{1}{3}+\dfrac{2}{3}=\dfrac{1+2}{3}=\dfrac{3}{3}=1\)
2) \(\dfrac{4}{5}+\dfrac{5}{6}=\dfrac{24}{30}+\dfrac{25}{30}=\dfrac{24+25}{30}=\dfrac{49}{30}\)
3) \(\dfrac{4}{5}-\dfrac{3}{5}=\dfrac{4-3}{5}=\dfrac{1}{5}\)
4) \(\dfrac{9}{8}-\dfrac{4}{2}=\dfrac{9}{8}-2=\dfrac{9}{8}-\dfrac{16}{8}=-\dfrac{7}{8}\)
5) \(\dfrac{8}{5}\times\dfrac{5}{8}=\dfrac{8\times5}{5\times8}=\dfrac{40}{40}=1\)
6) \(\dfrac{6}{7}\times\dfrac{4}{7}=\dfrac{6\times4}{7}=\dfrac{24}{7}\)
7) \(\dfrac{4}{5}:\dfrac{4}{5}=\dfrac{4}{5}\times\dfrac{5}{4}=\dfrac{4\times5}{5\times4}=\dfrac{20}{20}=1\)
8) \(\dfrac{5}{5}:\dfrac{5}{5}=\dfrac{5}{5}\times\dfrac{5}{5}=\dfrac{5\times5}{5\times5}=\dfrac{25}{25}=1\)