Tìm x biết: a) 7,5x : \(\left(9-6\frac{13}{21}\right)\)= \(2\frac{14}{25}\)
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TT
2
HT
24 tháng 7 2017
\(7,5x:\left(9-\frac{139}{21}\right)=\frac{63}{25}\)
\(7,5x:\left(\frac{189}{21}-\frac{139}{21}\right)=\frac{63}{25}\)
\(7,5x:\left(\frac{50}{21}\right)=\frac{63}{25}\)
\(7,5x=\frac{63}{25}.\frac{50}{21}\)
\(7,5x=6\)
\(x=6:7,5\)
\(x=\frac{4}{5}\)
vậy \(x=\frac{4}{5}\)
k mk nha vì mk đang âm điểm
AH
1
DK
5 tháng 8 2016
\(7,5x:\left[9-6\frac{13}{21}\right]=2\frac{13}{25}\)
\(\Leftrightarrow7,5x:\left[9-\frac{139}{21}\right]=\frac{63}{25}\)
\(\Leftrightarrow7,5x:\frac{50}{21}=\frac{63}{25}\)
\(\Leftrightarrow7,5x=\frac{63}{25}.\frac{50}{21}\)
\(\Leftrightarrow7,5x=6\)
\(\Leftrightarrow x=6:7,5\)
\(\Leftrightarrow x=\frac{4}{5}=0,8\)
(Chúc bạn học tốt và tíck cho mìk vs nha!)
6 tháng 8 2019
\(x:(3\frac{1}{2}-5\frac{1}{6})=4\frac{1}{5}-6\frac{2}{3}\) b,\((2\frac{1}{3}+3\frac{1}{2})\cdot x=-4\frac{1}{4}+3\frac{1}{7}\)
\(x:\frac{-5}{3}\)=\(\frac{-37}{15}\) \(\frac{35}{6}\cdot x=\)\(\frac{-31}{28}\)
\(x=\frac{-37}{15}\cdot\frac{-5}{3}\) \(x=\frac{-31}{28}:\)\(\frac{35}{6}\)
\(x=\frac{37}{9}\) \(x=\frac{-93}{490}\)
Vậy x=\(\frac{37}{9}\) Vậy x=\(\frac{-93}{490}\)
7,5x:\((9-6\frac{13}{21})=2\frac{13}{25}\)
7,5x:\(\frac{50}{21}\)=\(\frac{63}{25}\)
7,5x=\(\frac{63}{25}:\frac{50}{21}=\frac{1323}{1250}\)
x=\(\frac{1323}{1250}:7,5\)
x=\(\frac{441}{3125}\)
Vậy x=\(\frac{441}{3125}\)
T
0
T
0
5 tháng 8 2016
a) \(\frac{2}{\left(x+2\right).\left(x+4\right)}+\frac{4}{\left(x+4\right).\left(x+8\right)}+\frac{6}{\left(x+8\right).\left(x+14\right)}=\frac{x}{\left(x+2\right).\left(x+14\right)}\)
\(\Rightarrow\frac{1}{x+2}-\frac{1}{x+4}+\frac{1}{x+4}-\frac{1}{x+8}+\frac{1}{x+8}-\frac{1}{x+14}=\frac{x}{\left(x+2\right).\left(x+14\right)}\)
\(\Rightarrow\frac{1}{x+2}-\frac{1}{x+14}=\frac{x}{\left(x+2\right).\left(x+14\right)}\)
\(\Rightarrow\frac{x+14}{\left(x+2\right).\left(x+14\right)}-\frac{x+2}{\left(x+2\right).\left(x+14\right)}=\frac{x}{\left(x+2\right).\left(x+14\right)}\)
\(\Rightarrow\frac{x+14-x+2}{\left(x+2\right).\left(x+14\right)}=\frac{x}{\left(x+2\right).\left(x+14\right)}\)
\(\Rightarrow\frac{16}{\left(x+2\right).\left(x+4\right)}=\frac{x}{\left(x+2\right).\left(x+14\right)}\)
\(\Rightarrow x=16\)
Vậy x = 16
5 tháng 8 2016
\(b,\frac{x+1}{10}+\frac{x+1}{11}+\frac{x+1}{12}=\frac{x+1}{13}+\frac{x+1}{14}\)
\(\Leftrightarrow\frac{x+1}{10}+\frac{x+1}{11}+\frac{x+1}{12}-\frac{x+1}{13}-\frac{x+1}{14}=0\)
\(\Leftrightarrow\left(x+1\right)\left(\frac{1}{10}+\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\right)=0\)
\(\Leftrightarrow x+1=0\left(vì\frac{1}{10}+\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\ne0\right)\)
\(\Leftrightarrow x=-1\)
\(\text{Vậy }x=-1\)
1 tháng 8 2016
b. (x+1)(1/10+1/11+1/12-1/13-1/14)=0
x+1=0 (vì : 1/10+1/11+1/12-1/13-1/14>0)
x=-1
7,5x:\(\frac{50}{21}\)=\(\frac{64}{25}\)
7,5x = \(\frac{64}{25}.\frac{50}{21}\)
7,5x = \(\frac{128}{21}\)
x = \(\frac{128}{21}:7,5\)
x = \(\frac{256}{315}\)
256
315