Đáp án:
Bài `1:`
`a)-1/3-2/3:x=1/6`
`=>-1:x=1/6`
`=>x=-1/6.1`
`=>x=-1/6`
`->x={-1/6}`
`b)(x-1/2)^2=1/4`
`=>(x-1)^2=+-(1/2)^2`
$\Rightarrow\left[\begin{matrix} x-1=\dfrac{1}{2}\\ x-1=-\dfrac{1}{2}\end{matrix}\right.\Leftrightarrow\left[\begin{matrix} x=\dfrac{3}{2}\\ x=\dfrac{1}{2}\end{matrix}\right.$
`->x={3/2;1/2}`
`c)(x-1/2)^3=-1/8`
`=>(x-1/2)^3=(-1/2)^3`
`=>x-1/2=-1/2`
`=>x=0`
`->x={0}`
`d)|2x-1/2|=1/2`
$\Rightarrow\left[\begin{matrix} 2x-\dfrac{1}{2}=\dfrac{1}{2}\\ 2x-\dfrac{1}{2}=-\dfrac{1}{2}\end{matrix}\right.\Leftrightarrow\left[\begin{matrix} 2x=1\\ 2x=0\end{matrix}\right.\Leftrightarrow\left[\begin{matrix} x=\dfrac{1}{2}\\ x=0\end{matrix}\right.$
`->x={1/2;0}`
`e)3/7x-2/3x=10/21`
`=>x(3/7-2/3)=10/21`
`=>-5/21x=10/21`
`=>x=10/21:(-5/21)`
`=>x=-2`
`->x={-2}`
Bài `2:`
`a)-1/2. 3/4-1/2.5`
`=[(-1/2). 1/2]-(3/4. 5)`
`=-1/4-15/4`
`=-16/4=-4/4=-1`
`b)12/25. 23/7-12/25. 12/7`
`=12/25(23/7-12/7)`
`=12/25. 11/7`
`=132/175`
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