Question

\(\left(2x+1\right)^2=\dfrac{36}{25}\)

Answer 1

\(\left(2x+1\right)^2=\left(\dfrac{6}{5}\right)^2\\ 2x+1=\dfrac{6}{5}\) 

Còn lại tự tính;-;

Answer 2

\(\Leftrightarrow\left[{}\begin{matrix}2x+1=\dfrac{6}{5}\\2x+1=-\dfrac{6}{5}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=\dfrac{1}{5}\\2x=-\dfrac{11}{5}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{10}\\x=-\dfrac{11}{10}\end{matrix}\right.\)

Answer 3

\(\left(2x+1\right)^2=\dfrac{36}{25}\\ \Leftrightarrow\left[{}\begin{matrix}\left(2x+1\right)^2=\left(\dfrac{6}{5}\right)^2\\\left(2x+1\right)^2=\left(-\dfrac{6}{5}\right)^2\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}2x+1=\dfrac{6}{5}\\2x+1=-\dfrac{6}{5}\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}2x=\dfrac{1}{5}\\2x=-\dfrac{11}{5}\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{10}\\x=-\dfrac{11}{10}\end{matrix}\right.\\ \Rightarrow S=\text{ }\left\{-\dfrac{11}{10};\dfrac{1}{10}\right\}\)