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 \(x=\frac{45}{4}\)
