Question

tìm x, biết:

|7 - 2x| - 4 > 2x

Answer 1

Ta có: \(\left|7-2x\right|-4>2x\)

\(\Leftrightarrow\left|7-2x\right|>2x+4\)

\(\Leftrightarrow\left[{}\begin{matrix}7-2x>2x+4\\7-2x< -2x-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}7-2x-2x-4>0\\7-2x+2x+4< 0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}-4x+3>0\\11< 0\left(loại\right)\end{matrix}\right.\Leftrightarrow-4x>-3\)

hay \(x< \frac{3}{4}\)

Vậy: S={x|\(x< \frac{3}{4}\)}