2.Tìm x,bt: a.Ix-1/4I+0,75=1,75 b.2x+3/4=1/2 c.2/3x-(-1/2)mũ 2=căn 9/16 Helpppp mn lm chi tiết jup mk vs ak Mk đg cần gấp

`a)|x-1/4|+0,75=1,75`

`<=>|x-1/4|=1`

`<=>`$\left[\begin{matrix} x-\dfrac{1}{4}=1\\ x-\dfrac{1}{4}=-1\end{matrix}\right.$

`<=>`$\left[\begin{matrix} x=\dfrac{5}{4}\\ x=-\dfrac{3}{4}\end{matrix}\right.$

Vậy `x=5/4` hoặc `x=-3/4`

`b)2x+3/4=1/2`

`<=>2x=-1/4`

`<=>x=-1/8`

Vậy `x=-1/8`

`c)2/3x-(-1/2)^2=\sqrt{9/16}`

`<=>2/3x-1/4=\sqrt{(3/4)^2}`

`<=>2/3x-1/4=3/4`

`<=>2/3x=1`

`<=>x=3/2`

Vậy `x=3/2`