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\(\frac{1}{3}x:\frac{2}{3}=1\frac{3}{4}:\frac{2}{5}\)
\(\Rightarrow\frac{1}{3}x:\frac{2}{3}=\frac{35}{8}\)
\(\Rightarrow\frac{1}{3}x=\frac{35}{12}\)
\(\Rightarrow x=\frac{35}{4}\)
a) \(\left(\frac{1}{3}\cdot x\right):\frac{2}{3}=1\frac{3}{4}:\frac{2}{5}\)
\(=\left(\frac{1}{3}\cdot x\right):\frac{2}{3}=\frac{35}{8}\)
\(\Rightarrow\frac{1}{3}\cdot x=\frac{35}{8}\cdot\frac{2}{3}\)
\(\Rightarrow x=\frac{35}{12}:\frac{1}{3}=\frac{35}{4}\)
b) \(4,5:0,3=2,5:\left(0,1\cdot x\right)\)
\(=15=2,5:\left(0,1\cdot x\right)\)
\(\Rightarrow0,1\cdot x=2,25:15\)
\(\Rightarrow x=\frac{3}{20}:0,1=\frac{3}{2}=1,5\)
c) \(8:\left(\frac{1}{4}\cdot x\right)=2:0,02\)
\(8:\left(\frac{1}{4}\cdot x\right)=100\)
\(\Rightarrow\frac{1}{4}\cdot x=8:100\)
\(\Rightarrow x=\frac{2}{25}:\frac{1}{4}=\frac{8}{25}=0,32\)
d) \(3:2\frac{1}{4}=\frac{3}{4}:\left(6\cdot x\right)\)
\(=\frac{4}{3}=\frac{3}{4}:\left(6:x\right)\)
\(\Rightarrow6\cdot x=\frac{3}{4}:\frac{4}{3}\)
\(\Rightarrow x=\frac{9}{16}:6=\frac{3}{32}=0,09375\)
P/s : Vì bạn lớp 7 nên mình giải chi tiết nha!
Có \(\frac{x-1}{x+2}=\frac{x-2}{x+3}\Leftrightarrow\left(x-1\right)\left(x+3\right)=\left(x+2\right)\left(x-2\right)\)
\(\Leftrightarrow x\left(x+3\right)-1\left(x+3\right)=x\left(x-2\right)+2\left(x-2\right)\)
\(\Leftrightarrow x^2+3x-x-3=x^2-2x+2x-4\)
\(\Leftrightarrow x^2+\left(3x-x\right)-3=x^2+\left(2x-2x\right)-4\)
\(\Leftrightarrow x^2+2x-3=x^2-4\Leftrightarrow x^2-x^2+2x=3-4=-1\)
\(=\left(x^2-x^2\right)+2x=-1\Leftrightarrow2x=1\Leftrightarrow x=1\div2=\frac{1}{2}\)
\(\Leftrightarrow-\dfrac{8}{17}\left(\dfrac{5}{2}-3x\right)=\dfrac{5}{3}\left(2x+\dfrac{8}{5}\right)\)
\(\Leftrightarrow x\cdot\dfrac{24}{17}-\dfrac{20}{17}=\dfrac{10}{3}x+\dfrac{8}{3}\)
\(\Leftrightarrow x\cdot\dfrac{-98}{51}=\dfrac{196}{51}\)
hay x=-2
\(\frac{x-1}{x-2}=\frac{x+3}{x+4}\)
\(\Rightarrow\left(x-1\right)\left(x+4\right)=\left(x-2\right)\left(x+3\right)\)
\(\Leftrightarrow x^2+4x-x-4=x^2+3x-2x-6\)
\(\Leftrightarrow x^2+4x-x-4-x^2-3x+2x+6=0\)
\(\Leftrightarrow2x+2=0\)
\(\Leftrightarrow2x=-2\)
\(\Leftrightarrow x=-1\)VẬY X=-1 LÀ NGHIỆM CỦA PHƯƠNG TRÌNH \(\frac{x-1}{x-2}=\frac{x+3}{x+4}\)
0,15 : 3\(\sqrt{x}=0,3:\frac{2}{3}\)
=> 0,15 : \(3\sqrt{x}=0,45\)
=> \(3\sqrt{x}=\frac{1}{3}\)
=>\(\sqrt{x}=\frac{1}{9}\)
=> x = \(\left(\frac{1}{9^{ }}\right)2\)
=> x = \(\frac{1}{81}\)