a/ 4x ( 2x -5) - 3(2x -5) =0
( 2x -5) (4x -3) =o
.(2x -5) =0 suy ra x = 2,5
. (4x -3 ) = 0 suy ra x= 0,75
câu b làm tương tự bạn nhé !
c/x^3 -10x^2 + 16x =0
x( x^2 -10x + 16)=0
.x=0
.(x^2 -10x +16) =0 suy ra x =2
a) 4x( 2x - 5 ) + 3 ( 5 - 2x ) = 0
4x( 2x - 5 ) - 3 ( 2x - 5 ) = 0
( 4x - 3 ) ( 2x - 5 ) = 0
\(\Rightarrow\left[{}\begin{matrix}4x-3=0\Rightarrow x=\dfrac{3}{4}\\2x-5=0\Rightarrow x=\dfrac{5}{2}\end{matrix}\right.\)
b) 3( 2x - 1 ) = x ( 1 - 2x )
=> 3( 2x - 1 ) - x( 1 - 2x ) = 0
3 ( 2x - 1 ) + x ( 2x - 1 ) = 0
3x ( 2x - 1 ) = 0
\(\Rightarrow\left[{}\begin{matrix}3x=0\Rightarrow x=0\\2x-1=0\Rightarrow x=\dfrac{1}{2}\end{matrix}\right.\)
c) x3 - 10x2 = -16x
x3 - 10x2 + 16x = 0
x3 - 2x2 - 8x2 + 16x = 0
x2 ( x - 2 ) - 8x ( x - 2 ) = 0
( x2 - 8x ) ( x - 2 ) = 0
x ( x - 8 ) ( x - 2 ) = 0
=> x = 0
hoặc x - 8 = 0 => x = 8
hoặc x - 2 = 0 => x = 2