Question

tìm x biết |2x+3|=x+2

Answer 1

\(\left[{}\begin{matrix}2x+3=x+2\\2x+3=-x-2\end{matrix}\right.< =>\left[{}\begin{matrix}x=-1\\x=-\dfrac{5}{3}\end{matrix}\right.\)

Answer 2

\(\Leftrightarrow\left\{{}\begin{matrix}x>=-2\\\left(2x+3\right)^2-\left(x+2\right)^2=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ge-2\\\left(2x+3-x-2\right)\left(2x+3+x+2\right)=0\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x\ge-2\\\left(x+1\right)\left(3x+5\right)=0\end{matrix}\right.\Leftrightarrow x\in\left\{-1;-\dfrac{5}{3}\right\}\)