Bài 2: (2,0 điểm) Tìm x, biết: a) (-$\frac{1}{2}$) + ($\frac{4}{5}$ + x) = 1$\frac{1}{2}$ b) (x - $\frac{1}{3}$)² = $\frac{1}{9}$ c) 5.$\sqrt{x}$ - $\sqrt{\frac{1}{25}}$ = 0 d) |0,3 - x| = $\frac{1}{3}$

`a)(-1/2)+(4/5+x)=1 1/2`

`-1/2+4/5+x=1 1/2`

`3/10+x=3/2`

`x=3/2-3/10`

`x=15/10-3/10`

`x=1,2`

Vậy `x=1,2`

`b)(x-1/3)^2=1/9`

`(x-1/3)^2=(1/3)^2`

`x-1/3=1/3`

`x=1/3+1/3`

`x=2/3`

Vậy `x=2/3`

`c)5*`$\sqrt{x}$`-`$\sqrt{\dfrac{1}{25}}$`=0`

`5*`$\sqrt{x}$`-1/5=0`

`5*`$\sqrt{x}$`=1/5`

$\sqrt{x}$`=1/5:5`

$\sqrt{x}$`=1/25`

`=>x=+-1/625`

Vậy `x=+-1/625`

`d)0,3-x=1/3`

`TH_1:0,3-x=1/3`

`x=0,3-1/3`

`x=(-1)/30`

`TH_2:0,3-x=-1/3`

`x=0,3+1/3`

`x=19/30`

Vậy `x=(-1)/30;x=19/30`