giai nhanh giup minh dc ko a A) -|2x-3|= 4-x B) x^2= 9(x-1)^2

`#DyHung`

A) `ĐK:`

+) `2x-3` khi `2x-3 >= 0` hay `x >= 3/2` `(1)`

+) `3-2x` khi `2x-3 < 0` hat `x < 3/2` `(2)`

Với `ĐK (1)` ta đc:

`-(2x-3)=4-x`

`⇔-2x+3=4-x`

`⇔-x=1`

`⇔x=-1 (TKM)`

Với `ĐK (2)` ta được:  

`-(3-2x)=4-x`

`⇔-3+2x=4-x`

`⇔x=7(KTM)`

Vậy pt vô nghiệm

`B) x²=9(x-1)²`

`⇔x²=9(x²-2x+1)`

`⇔x²=9x²-18x+9`

`⇔-8x²+18x-9=0`

`⇔-(8x^2-18x+9)=0`

`⇔8x²-12x-6x+9=0`

`⇔(2x-3)(4x-3)=0`

`1) 2x-3=0⇔x=3/2`

`2) 4x-3=0⇔x=3/4`