Câu 8. (1,0 điểm) Tìm x biết: a) $\frac{4}{5}$x - $\frac{1}{3}$ = $\frac{2}{3}$ b) $\frac{2}{3,5}$ = $\frac{|x - 1|}{7}$

`Accnswer`

`a)4/5x-1/3=2/3`

`=>4/5x=2/3+1/3`

`=>4/5x=1`

`=>x=1:4/5`

`=>x=1 . 5/4`

`=>x=5/4`

Vậy `x=5/4`

`b)2/(3,5)=(|x-1|)/7`

`=>2.7=3,5.|x-1|`

`=>14=3,5.|x-1|`

`=>14=7/2 .|x-1|`

`=>|x-1|=14:7/2`

`=>|x-1|=14. 2/7`

`=>|x-1|=4`

`=>x+1=+-4`

`@TH_1:`

`x-1=4`

`=>x=4+1`

`=>x=5`

`@TH_2:`

`x-1=-4`

`=>x=-4+1`

`=>x=-3`

Vậy `x in{5;-3}`