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a, ( 152 +và 2/4 - 148 và 3/8 ) : 0,2 = x : 0,3
=> 33/8 : 1/5 = x : 3/10
=> x : 3/10 = 165/8
=> x = 99/10
b, ( 85 và 7/30 - 83 và 5/18 ) : 2 và 2/3 = 0,01x : 4
=> 88/45 : 8/3 = 0,01x : 4
=> 0,01x : 4 = 11/15
=> 0,01x = 44/15
=> x = 880/3
c, x - 1/ x + 5 = 6/7
=> 7( x - 1 ) = 6( x + 5 )
=> 7x - 7 = 6x + 30
=> 7x - 6x = 7 + 30
=> x = 37
d, x2/6 = 24/25
=> x2. 25 = 6 . 24
=> x2.25 = 144
=> x2 = 144/25
=> x = ( 12/5)2 hoặc x = ( -12/5)
g, x - 3/ x + 5 = 5/7
=> 7( x - 3 ) = 5 ( x + 5 )
=> 7x - 21 = 5x + 25
=> 7x - 5x = 21 + 25
=> 2x = 46
=> x = 23
\(G=\frac{1}{25}-\frac{4}{27}+\left(\frac{-23}{27}+\frac{-1}{25}-\frac{5}{43}\right)+\frac{5}{43}-\frac{4}{7}\)
\(=\frac{1}{25}-\frac{4}{27}+\frac{-23}{27}+\frac{-1}{25}-\frac{5}{43}+\frac{5}{43}-\frac{4}{7}\)
\(=\left(\frac{1}{25}+\frac{-1}{25}\right)+\left(\frac{-4}{27}+\frac{-23}{27}\right)+\left(\frac{-5}{43}+\frac{5}{43}\right)-\frac{4}{7}\)
\(=0+\left(-1\right)+0-\frac{4}{7}\)
\(=\frac{-11}{7}\)
a) \(\frac{5+x}{4-x}=\frac{1}{2}\)
10 + 2x = 4 - x
10 - 4 = -x - 2x
6 = -3x
=> x = 6/-3 = -2
b) \(\frac{25}{14}=\frac{x+7}{x-4}\)
25x - 100 = 14x + 98
25x - 14x = 98 + 100
11x = 198
=> x = 198/11 = 18
\(a,\frac{x-1}{x+5}=\frac{6}{7}\)
\(\Rightarrow7x-7=6x+30\)
\(\Rightarrow x=37\)
Vậy x=37
b) \(\frac{x^2}{6}=\frac{24}{25}\)
\(\Leftrightarrow x^2.25=6.24\)
\(\Leftrightarrow x^2.25=144\)
\(\Leftrightarrow x^2=\frac{144}{25}\)
\(\Leftrightarrow x=\pm\sqrt{\frac{144}{25}}=\pm\frac{12}{5}\)
a) \(2x\left(x-\frac{1}{7}\right)=0\)
⇒\(\left[{}\begin{matrix}2x=0\\x-\frac{1}{7}=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=0\\x=\frac{1}{7}\end{matrix}\right.\)
Vậy \(x=0;x=\frac{1}{7}\)
b) \(\frac{1}{2}x+\frac{3}{5}x=\frac{-33}{25}\\ \left(\frac{1}{2}+\frac{3}{5}\right)x=\frac{-33}{25}\\ \left(\frac{5}{10}+\frac{6}{10}\right)x=\frac{-33}{25}\\ \frac{11}{10}x=\frac{-33}{25}\\ x=\frac{-33}{25}:\frac{11}{10}\\ x=\frac{-33.10}{25.11}\\ x=\frac{-6}{5}\)
Vậy x = \(\frac{-6}{5}\)
c) \(\left(\frac{2}{3}x-\frac{4}{9}\right)\left(\frac{1}{2}+\frac{-3}{7}:x\right)=0\\ \Rightarrow\left[{}\begin{matrix}\frac{2}{3}x-\frac{4}{9}=0\\\frac{1}{2}+\frac{-3}{7}:x=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}\frac{2}{3}x=\frac{4}{9}\\\frac{-3}{7}:x=\frac{-1}{2}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{4}{9}:\frac{2}{3}=\frac{4.3}{9.2}=\frac{2}{3}\\x=\frac{-3}{7}:\frac{-1}{2}=\frac{-3.2}{7.\left(-1\right)}=\frac{6}{7}\end{matrix}\right.\)
a) \(2x\left(x-\frac{1}{7}\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}2x=0\\x-\frac{1}{7}=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=0:2=0\\x=0+\frac{1}{7}=\frac{1}{7}\end{matrix}\right.\)
b) \(\frac{1}{2}x+\frac{3}{5}x=-\frac{33}{25}\)
\(\Rightarrow x\left(\frac{1}{2}+\frac{3}{5}\right)=-\frac{33}{25}\)
\(\Rightarrow x\frac{11}{10}=-\frac{33}{25}\)
\(\Rightarrow x=\left(-\frac{33}{25}\right):\frac{11}{10}=-\frac{33}{25}.\frac{10}{11}=-\frac{6}{5}\)
c) \(\left(\frac{2}{3}x-\frac{4}{9}\right)\left(\frac{1}{2}+\frac{-3}{7}:x\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}\frac{2}{3}x-\frac{4}{9}=0\\\frac{1}{2}+\frac{-3}{7}:x=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}\frac{2}{3}x=0+\frac{4}{9}=\frac{4}{9}\\-\frac{3}{7}:x=0-\frac{1}{2}=-\frac{1}{2}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\frac{4}{9}:\frac{2}{3}=\frac{4}{9}.\frac{3}{2}=\frac{2}{3}\\x=\left(-\frac{3}{7}\right):\frac{-1}{2}=\left(-\frac{3}{7}\right).\left(-2\right)=\frac{6}{7}\end{matrix}\right.\)
Bài 1
\(=-\frac{21}{60}=-\frac{7}{20}\)
\(b,\left(2-\frac{1}{3}\right)^2+|-\frac{5}{6}|+\frac{-7}{12}-\frac{25}{9}\)
\(=\frac{25}{9}+\frac{5}{6}-\frac{7}{12}-\frac{25}{9}\)
\(=\left(\frac{25}{9}-\frac{25}{9}\right)+\left(\frac{5}{6}-\frac{7}{12}\right)\)
\(=0+\frac{1}{4}=\frac{1}{4}\)
Bài 2
\(a,x+\frac{2}{5}=-\frac{3}{10}\)
\(x=-\frac{3}{10}-\frac{2}{5}\)
\(x=-\frac{3}{10}-\frac{4}{10}\)
\(x=-\frac{7}{10}\)
\(b,|\frac{2}{3}+x|=\frac{5}{7}\)
\(\Rightarrow\orbr{\begin{cases}\frac{2}{3}+x=\frac{5}{7}\\\frac{2}{3}+x=-\frac{5}{7}\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{5}{7}-\frac{2}{3}\\x=-\frac{5}{7}-\frac{2}{3}\end{cases}\Rightarrow}\orbr{\begin{cases}x=\frac{1}{21}\\x=-\frac{29}{21}\end{cases}}}\)
== chắc trog quá trình lm lỡ xóa đó
\(a,-\frac{3}{4}.\frac{7}{15}\)
\(=-\frac{21}{60}=-\frac{7}{20}\)
với lại bài trên mk tính nhẩm ko bấm máy sai == sửa giúp
x = 7/25 + ( -1/5)
x = 7/25 + (-5/25)
x = 2/25
vậy x = 2/25
x=7/25+-1/5
x = 7/25 + ( -1/5)
x = 7/25 + (-5/25)
x = 2/25
vậy x = 2/25