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26 tháng 10 2019
\(135-5\cdot\left(x+4\right)=35\)
\(5\cdot\left(x+4\right)=135-35\)
\(5\cdot\left(x+4\right)=100\)
\(x+4=100:5\)
\(x+4=20\)
\(x=20-4\)
\(x=16\)
b) \(25+3\cdot\left(x-8\right)=106\)
\(3\cdot\left(x-8\right)=106-25\)
\(3\cdot\left(x-8\right)=81\)
\(x-8=81:3\)
\(x-8=27\)
\(x=27+8\)
\(x=35\)
c) \(3^2\cdot\left(x+4\right)-5^2=5\cdot2^2\)
\(9\cdot\left(x+4\right)-25=5\cdot4\)
\(9\cdot\left(x+4\right)-25=20\)
\(9\cdot\left(x+4\right)=20+25\)
\(9\cdot\left(x+4\right)=45\)
\(x+4=45:9\)
\(x+4=5\)
\(x=5-4\)
\(x=1\)
Chúc bạn học tốt!!!!!!!!!!!!!!!!!!!!
MV
23 tháng 4 2017
9) \(\dfrac{x}{4}=\dfrac{9}{x}\)
Theo định nghĩa về hai phân số bằng nhau, ta có:
\(4\cdot9=x^2\\ 36=x^2\Rightarrow\left[{}\begin{matrix}x=6\\x=-6\end{matrix}\right.\)
8)
\(x:\dfrac{5}{3}+\dfrac{1}{3}=-\dfrac{2}{5}\\ x:\dfrac{5}{3}=-\dfrac{2}{5}+\dfrac{1}{3}\\ x:\dfrac{5}{3}=-\dfrac{1}{15}\\ x=\dfrac{1}{15}\cdot\dfrac{5}{3}\\ x=\dfrac{1}{9}\)
7)
\(2x-16=40+x\\ 2x-x=40+16\\ x\left(2-1\right)=56\\ x=56\)
6)
\(1\dfrac{1}{2}+x=\dfrac{3}{2}-7\\ \dfrac{3}{2}+x=\dfrac{3}{2}-7\\ \dfrac{3}{2}-\dfrac{3}{2}=-7-x\\ -7-x=0\\ x=-7-0\\ x=-7\)
5)
\(3\dfrac{1}{2}-\dfrac{1}{2}x=\dfrac{2}{3}\\ \dfrac{7}{2}-\dfrac{1}{2}x=\dfrac{2}{3}\\ \dfrac{1}{2}x=\dfrac{7}{2}-\dfrac{2}{3}\\ \dfrac{1}{2}x=\dfrac{17}{6}\\ x=\dfrac{17}{6}:\dfrac{1}{2}\\ x=\dfrac{17}{3}\)
4)
\(x\cdot\left(x+1\right)=0\Rightarrow\left[{}\begin{matrix}x=0\\x+1=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=0\\x=-1\end{matrix}\right.\)
3)
\(\left(\dfrac{2x}{5}+2\right):\left(-4\right)=-1\dfrac{1}{2}\\ \left(\dfrac{2x}{5}+2\right):\left(-4\right)=-\dfrac{3}{2}\\ \dfrac{2x}{5}+2=-\dfrac{3}{2}\cdot\left(-4\right)\\ \dfrac{2x}{5}+2=6\\ \dfrac{2x}{5}=6-2\\ \dfrac{2x}{5}=4\\ 2x=4\cdot5\\ 2x=20\\ x=20:2\\ x=10\)
2)
\(\dfrac{1}{3}+\dfrac{1}{2}:x=-0,25\\ \dfrac{1}{3}+\dfrac{1}{2}:x=-\dfrac{1}{4}\\ \dfrac{1}{2}:x=-\dfrac{1}{4}-\dfrac{1}{3}\\ \dfrac{1}{2}:x=-\dfrac{7}{12}\\ x=\dfrac{1}{2}:-\dfrac{7}{12}\\ x=-\dfrac{6}{7}\)
1)
\(\dfrac{4}{3}+x=\dfrac{2}{15}\\ x=\dfrac{2}{15}-\dfrac{4}{3}x=-\dfrac{6}{5}\)
6 tháng 3 2017
Ta có: \(\left(2008-\dfrac{2}{135}+\dfrac{1}{50}\right)-\left(1-\dfrac{7}{135}+\dfrac{4}{150}\right)-\left(5+\dfrac{5}{135}+\dfrac{3}{50}\right)\)
= \(2008-\dfrac{2}{135}+\dfrac{1}{50}-1+\dfrac{7}{135}-\dfrac{4}{150}-5-\dfrac{5}{135}-\dfrac{3}{50}\)
= (2008-1-5) + \(\left(\dfrac{1}{50}-\dfrac{3}{50}\right)-\left(\dfrac{2}{135}-\dfrac{7}{135}\right)-\dfrac{4}{150}\)
=2002 \(-\dfrac{1}{25}\)+\(\dfrac{1}{27}\)\(-\dfrac{4}{150}\)
=2001,9(3)
15 tháng 8 2019
Tìm x :
a) \(2.x.\frac{-3}{4}=-\frac{5}{12}\)
\(\Rightarrow2x=-\frac{5}{12}:-\frac{3}{4}\)
\(\Rightarrow2x=\frac{5}{9}\)
\(\Rightarrow x=\frac{5}{9}:2\)
\(\Rightarrow x=\frac{5}{18}\)
Vậy : \(x=\frac{5}{18}\)
b) \(\frac{2}{3}+\frac{1}{3}.x=7\)
\(\Rightarrow\frac{1}{3}.x=7-\frac{2}{3}\)
\(\Rightarrow\frac{1}{3}.x=\frac{19}{3}\)
\(\Rightarrow x=\frac{19}{3}:\frac{1}{3}\)
\(\Rightarrow x=19\)
Vậy : \(x=19\)
c) \(\left(4.x+\frac{1}{8}\right)=\frac{3}{10}\)
\(\Rightarrow4.x=\frac{3}{10}-\frac{1}{8}\)
\(\Rightarrow4.x=\frac{7}{40}\)
\(\Rightarrow x=\frac{7}{40}:4\)
\(\Rightarrow x=\frac{7}{160}\)
Vậy : \(x=\frac{7}{160}\)
d) \(\frac{1}{3}.x-5=1\frac{1}{2}\)
\(\Rightarrow\frac{1}{3}.x-5=\frac{3}{2}\)
\(\Rightarrow\frac{1}{3}.x=\frac{3}{2}+5\)
\(\Rightarrow\frac{1}{3}.x=\frac{13}{2}\)
\(\Rightarrow x=\frac{13}{2}:\frac{1}{3}\)
\(\Rightarrow x=\frac{39}{2}\)
Vậy : \(x=\frac{39}{2}\)
e) \(-\frac{2}{3}.x+\frac{1}{3}=-\frac{1}{2}\)
\(\Rightarrow-\frac{2}{3}.x=-\frac{1}{2}-\frac{1}{3}\)
\(\Rightarrow-\frac{2}{3}.x=-\frac{5}{6}\)
\(\Rightarrow x=-\frac{5}{6}:\left(-\frac{2}{3}\right)\)
\(\Rightarrow x=\frac{5}{4}\)
Vậy : \(x=\frac{5}{4}\)
TC
30 tháng 6 2019
X : \(3\frac{1}{15}\)=\(1\frac{1}{2}\)
X : \(\frac{46}{15}\)=\(\frac{3}{2}\)
X = \(\frac{3}{2}\)X \(\frac{46}{15}\)
X = \(\frac{23}{5}\)
T
30 tháng 6 2019
#)Giải :
\(x\div3\frac{1}{5}=1\frac{1}{2}\)
\(\Leftrightarrow x\div\frac{16}{5}=\frac{3}{2}\)
\(\Leftrightarrow x=\frac{24}{5}\)hay \(4\frac{4}{5}\)
\(\frac{2}{3}x-\frac{1}{2}x=\frac{5}{12}\)
\(\Leftrightarrow\left(\frac{2}{3}-\frac{1}{2}\right)x=\frac{5}{12}\)
\(\Leftrightarrow\frac{1}{6}x=\frac{5}{12}\)
\(\Leftrightarrow x=\frac{5}{2}\)
13 tháng 7 2017
a) \(-\dfrac{2}{3}\left(x-\dfrac{1}{4}\right)=\dfrac{1}{3}\left(2x-1\right)\)
\(\Rightarrow-\dfrac{2}{3}x+\dfrac{1}{6}=\dfrac{2}{3}x-\dfrac{1}{3}\)
\(\Rightarrow\dfrac{1}{6}+\dfrac{1}{3}=\dfrac{2}{3}x+\dfrac{2}{3}x\)
\(\Rightarrow\dfrac{1}{2}=\dfrac{4}{3}x\)
\(\Rightarrow x=\dfrac{1}{2}:\dfrac{4}{3}=\dfrac{3}{8}\)
Vậy \(x=\dfrac{3}{8}\).
\(2\times3^{x+1}+3^{x+2}=135\)
\(3^{x+1}\left(2+3\right)=135\)
\(3^{x+1}\times5=135\)
\(3^{x+1}=\frac{135}{5}\)
\(3^{x+1}=27\)
\(3^{x+1}=3^3\)
x + 1 = 3
x = 3 - 1
x = 2