\(\sqrt{\dfrac{12x+5}{2}}=2\)

\(\sqrt{6x+\dfrac{5}{2}}=2\)

\(6x+\dfrac{5}{2}=4\)

\(6x=4-\dfrac{5}{2}\)

\(6x=\dfrac{3}{2}\)

`=>x=1/4`

\(\sqrt{\left(x-3\right)^2}=3\)

\(\left[{}\begin{matrix}x-3=3\\x-3=-3\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=6\\x=0\end{matrix}\right.\)

\(\left(-\dfrac{11}{3}x-0,2\right)^2=\dfrac{25}{36}\)

\(\left(-\dfrac{11}{3}x-\dfrac{1}{5}\right)^2=\dfrac{5^2}{6^2}\)

\(\left[{}\begin{matrix}-\dfrac{11}{3}x-\dfrac{1}{5}=\dfrac{5}{6}\\-\dfrac{11}{3}x-\dfrac{1}{5}=-\dfrac{5}{6}\end{matrix}\right.\)

\(\left[{}\begin{matrix}-\dfrac{11}{3}x=\dfrac{31}{30}\\-\dfrac{11}{3}x=-\dfrac{19}{30}\end{matrix}\right.\)

\(\left[{}\begin{matrix}x=-\dfrac{31}{110}\\x=\dfrac{19}{110}\end{matrix}\right.\)

`=>`\(x\in\left\{-\dfrac{31}{110};\dfrac{19}{110}\right\}\)

\(\left(\dfrac{3}{8}x-\dfrac{11}{5}\right)\cdot\left(-\dfrac{2}{7}x+0,85\right)=0\)

`=>`\(\left[{}\begin{matrix}\dfrac{3}{8}x-\dfrac{11}{5}=0\\-\dfrac{2}{7}x+\dfrac{17}{20}=0\end{matrix}\right.\)

\(\left[{}\begin{matrix}\dfrac{3}{8}x=\dfrac{11}{5}\\-\dfrac{2}{7}x=-\dfrac{17}{20}\end{matrix}\right.\)

\(\left[{}\begin{matrix}x=\dfrac{11}{5}\cdot\dfrac{8}{3}\\x=\left(-\dfrac{17}{20}\right)\cdot\left(-\dfrac{7}{2}\right)\end{matrix}\right.\)

\(\left[{}\begin{matrix}x=\dfrac{88}{15}\\x=\dfrac{119}{40}\end{matrix}\right.\)

`=>`\(x\in\left\{\dfrac{88}{15};\dfrac{119}{40}\right\}\)

a) \(\dfrac{21^2}{81}=\dfrac{21^2}{9^2}=\dfrac{7^2}{3^2}=\dfrac{49}{9}\)

b) \(\dfrac{5}{\sqrt{6}+1}-\dfrac{6-2\sqrt{6}}{2-\sqrt{6}}+\dfrac{2\sqrt{3}}{\sqrt{3}+\sqrt{2}}\)

\(=\sqrt{6}-1+\sqrt{6}+6-2\sqrt{6}\)

`=5`

copy gg mà có làm đâu

chắc là có :D

\(2^x+2^{x+3}=144\)

\(2^x\cdot1+2^x\cdot2^3=144\)

\(2^x\cdot\left(1+2^3\right)=144\)

\(2^x\cdot9=144\)

\(2^x=\dfrac{144}{9}\)

\(2^x=16\)

`2^x=2^4`

`=>x=4`