Question

Tìm x < 0 biết |x-2|+3|2-x|+|4x-8|=32 vậy x =

Answer 1

\(\left|x-2\right|+3\left|2-x\right|+\left|4x-8\right|=32\)

\(\Leftrightarrow\left|x-2\right|+3\left|x-2\right|+4\left|x-2\right|=32\)

Đặt \(t=\left|x-2\right|\) ta có:

\(t+3t+4t=32\)\(\Leftrightarrow8t=32\Leftrightarrow t=4\)

\(\left|x-2\right|=4\)\(\Leftrightarrow\left[\begin{matrix}x-2=4\\x-2=-4\end{matrix}\right.\)\(\Leftrightarrow x=-2\left(x< 0\right)\)

Answer 2

lưu ý |2-x|=|2-x| rút ra đjăt ẩn..