1/ $|2x-1|=\begin{cases}2x-1\,\,nếu\,\,2x-1≥0\,\,hay\,\,x≥\dfrac{1}{2}\\1-2x\,\,nếu\,\,2x-1<0\,\,hay\,\,x<\dfrac{1}{2}\end{cases}$
Với $x≥\dfrac{1}{2}→Q=3x-4-2x+1=x-3$
Với $x<\dfrac{1}{2}→Q=3x-4-1+2x=5x-5$
Vậy $Q=x-3$ với $x≥\dfrac{1}{2}$, $Q=5x-5$ với $x<\dfrac{1}{2}$
2/ $0,25-|1,5-x|=0\\↔|1,5-x|=0,25\\↔\left[\begin{array}{1}1,5-x=0,25\\1,5-x=-0,25\end{array}\right.\\↔\left[\begin{array}{1}x=1,25\\x=1,75\end{array}\right.$
Vậy x=1,25 hoặc x=1,75
