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a) \(\frac{1}{2}+\frac{2}{3}:x=\frac{3}{4}\)
=> \(\frac{2}{3}:x=\frac{3}{4}-\frac{1}{2}\)
=> \(\frac{2}{3}:x=\frac{1}{4}\)
=> \(x=\frac{2}{3}:\frac{1}{4}=\frac{8}{3}\)
b) \(5,4-3\left|x-\frac{21}{10}\right|=0\)
=> \(3\left|x-\frac{21}{10}\right|=\frac{27}{5}\)
=> \(\left|x-\frac{21}{10}\right|=\frac{27}{5}:3=\frac{9}{5}\)
=> \(\left|x-\frac{21}{10}\right|=\frac{9}{5}\)
Trường hợp 1 : \(x-\frac{21}{10}=\frac{9}{5}\)
=> \(x=\frac{9}{5}+\frac{21}{10}=\frac{39}{10}\)
Trường hợp 2 : \(x-\frac{21}{10}=-\frac{9}{5}\)
=> \(x=-\frac{9}{5}+\frac{21}{10}=\frac{3}{10}\)
Vậy : ...
c) \(10\sqrt{x-5}=25\)
=> \(\sqrt{x-5}=\frac{5}{2}\)
=> \(\left(x-5\right)^2=\frac{25}{4}\)
Trường hợp 1 :
\(x-5=\frac{25}{4}\)=> \(x=\frac{25}{4}+5=\frac{45}{4}\)
Trường hợp 2 :
\(x-5=-\frac{25}{4}\)=> \(x=-\frac{25}{4}+5=-\frac{5}{4}\)(loại)
Vậy \(x=\frac{45}{4}\)
a)
\(\begin{array}{l}x + \left( { - \frac{1}{5}} \right) = \frac{{ - 4}}{{15}}\\x = \frac{{ - 4}}{{15}} + \frac{1}{5}\\x = \frac{{ - 4}}{{15}} + \frac{3}{{15}}\\x = \frac{{ - 1}}{{15}}\end{array}\)
Vậy \(x = \frac{{ - 1}}{{15}}\).
b)
\(\begin{array}{l}3,7 - x = \frac{7}{{10}}\\x = 3,7 - \frac{7}{{10}}\\x = \frac{{37}}{{10}} - \frac{7}{{10}}\\x=\frac{30}{10}\\x = 3\end{array}\)
Vậy \(x = 3\).
c)
\(\begin{array}{l}x.\frac{3}{2} = 2,4\\x.\frac{3}{2} = \frac{{12}}{5}\\x = \frac{{12}}{5}:\frac{3}{2}\\x = \frac{{12}}{5}.\frac{2}{3}\\x = \frac{8}{5}\end{array}\)
Vậy \(x = \frac{8}{5}\)
d)
\(\begin{array}{l}3,2:x = - \frac{6}{{11}}\\\frac{{16}}{5}:x = - \frac{6}{{11}}\\x = \frac{{16}}{5}:\left( { - \frac{6}{{11}}} \right)\\x = \frac{{16}}{5}.\frac{{ - 11}}{6}\\x = \frac{{ - 88}}{{15}}\end{array}\)
Vậy \(x = \frac{{ - 88}}{{15}}\).
e)
\(\left(x+3\right)^3=\left(x+3\right)^5\)
\(\Rightarrow\)\(x+3=1;0\)
TH1: TH2
\(x+3=0\) \(x+3=1\)
\(x=-3\) \(x=-2\)
\(x\in\left\{-3;-2\right\}\)
1. A = 75(42004 + 42003 +...+ 42 + 4 + 1) + 25
A = 25 . [3 . (42004 + 42003 +...+ 42 + 4 + 1) + 1]
A = 25 . (3 . 42004 + 3 . 42003 +...+ 3 . 42 + 3 . 4 + 3 + 1)
A = 25 . (3 . 42004 + 3 . 42003 +...+ 3 . 42 + 3 . 4 + 4)
A = 25 . 4 . (3 . 42003 + 3 . 42002 +...+ 3 . 4 + 3 + 1)
A =100 . (3 . 42003 + 3 . 42002 +...+ 3 . 4 + 3 + 1) \(⋮\) 100
giúp mk vs ạ!!
ở câu b mk sót ở cuối là =0 nha