Question

Tìm x biết 

\(\left|x+3\right|+x=3\)

Answer 1

\(\left|x+3\right|+x=3\)

\(\Leftrightarrow\left|x+3\right|=3-x\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}x-3=3-x\\x-3=-3-x\end{array}\right.\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}x+x=3+3\\x+x=-3+3\end{array}\right.\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}2x=6\\2x=0\end{array}\right.\Leftrightarrow\left[\begin{array}{nghiempt}x=3\left(ktm\right)\\x=0\left(tm\right)\end{array}\right.\)

Vậy \(x=0\) 

Answer 2

\(\left|x+3\right|+x=3\\ \Rightarrow\left|x+3\right|=3-x\\ \)

|x+3|=3-x chỉ khi x = 0