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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
a, \(\left|x+\frac{1}{3}\right|=0\Leftrightarrow x=-\frac{1}{3}\)
b, \(\left|\frac{5}{18}-x\right|-\frac{7}{24}=0\)
\(\Leftrightarrow\orbr{\begin{cases}\frac{5}{18}-x=\frac{7}{24}\\\frac{5}{18}-x=-\frac{7}{24}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=-\frac{1}{72}\\x=\frac{41}{72}\end{cases}}\)
c, \(\frac{2}{5}-\left|\frac{1}{2}-x\right|=6\Leftrightarrow\left|\frac{1}{2}-x\right|=-\frac{28}{5}\)vô lí
Vì \(\left|\frac{1}{2}-x\right|\ge0\forall x\)*luôn dương* Mà \(-\frac{28}{5}< 0\)
=> Ko có x thỏa mãn
\(|x+\frac{1}{3}|=0\)
\(< =>x+\frac{1}{3}=0< =>x=-\frac{1}{3}\)
\(|x+\frac{3}{4}|=\frac{1}{2}\)
\(< =>\orbr{\begin{cases}x+\frac{3}{4}=\frac{1}{2}\\x+\frac{3}{4}=-\frac{1}{2}\end{cases}}\)
\(< =>\orbr{\begin{cases}x=-\frac{1}{4}\\x=-\frac{5}{4}\end{cases}}\)
a) \(\frac{16}{2^x}=1\Leftrightarrow2^x=16\Leftrightarrow2^x=2^4\Leftrightarrow x=4\)
b)\(5^{x+2}=625\Leftrightarrow5^{x+2}=5^4\Leftrightarrow x+2=4\Leftrightarrow x=2\)
c)\(\frac{x+3}{8}=\frac{2}{x-3}\left(đk:x\ne3\right)\Leftrightarrow\left(x+3\right).\left(x-3\right)=2.8\Leftrightarrow x^2-9=16\Leftrightarrow x^2=25\Leftrightarrow\orbr{\begin{cases}x=5\\x=-5\end{cases}}\)
d)\(\frac{x^2}{6}=\frac{24}{25}\Leftrightarrow25x^2=24.6\Leftrightarrow\left(5x\right)^2=144\Leftrightarrow\orbr{\begin{cases}5x=12\\5x=-12\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{12}{5}\\x=-\frac{12}{5}\end{cases}}\)
a) 16=2^x \(\Leftrightarrow\)x=4
b)5^x+2=5^4\(\Leftrightarrow\)x+2=4\(\Leftrightarrow\)x=2
k đi, mk làm tiếp cho
a.
\(\frac{x-1}{x-5}=\frac{6}{7}\)
\(\left(x-1\right)\times7=6\times\left(x-5\right)\)
\(7x-7=6x-30\)
\(7x-6x=-30+7\)
\(x=-23\)
b.
\(\frac{x^2}{6}=\frac{24}{25}\)
\(x^2=\frac{24}{25}\times6\)
\(x^2=\frac{144}{25}\)
\(x^2=\left(\pm\frac{12}{5}\right)^2\)
\(x=\pm\frac{12}{5}\)
Vậy \(x=\frac{12}{5}\) hoặc \(x=-\frac{12}{5}\)
Ta có : \(\frac{x+1}{5}=\frac{x+2}{6}\)
\(\Rightarrow\left(x+1\right)6=5\left(x+2\right)\)
\(\Leftrightarrow6x+6=5x+10\)
\(\Leftrightarrow6x-5x=10-6\)
\(\Rightarrow x=4\)
\(\frac{x+1}{2}\)= \(\frac{8}{x+1}\)
x + 1 . x + 1 = 2 . 8
x . 2 = 16
x = 16 : 2
x = 8
a) \(\frac{x-2}{5}=\frac{3}{8}\)
(x-2).8=5.3
(x-2).8=15
x-2=15:8
x-2=\(\frac{15}{8}\)
x=\(\frac{15}{8}+2\)
x=\(\frac{31}{8}\)
b)\(\frac{x-1}{x+5}=\frac{6}{7}\)
(x-1).7=(x+5).6
7x-7=6x+30
7x=6x+30+7
7x=6x+37
7x-6x=37
x=37
c)\(\frac{x^2}{6}=\frac{24}{25}\)
\(x^2.25=6.24\)
\(x^2.25=144\)
\(x^2=144:25\)
\(x^2=\frac{144}{25}\)
\(x^2=\left(\frac{12}{5}\right)^2\)
\(x=\frac{12}{5}\)
\(\frac{x-2}{5}=\frac{3}{8}\)=>\(x-2=\frac{15}{8}\)
=>\(x=\frac{31}{8}\)
\(\frac{x^2}{6}=\frac{24}{25}\Rightarrow\)x2= \(\frac{144}{25}\)
=> x = \(\frac{12}{5}\)