Question

Tìm x:

a. 2x ( x - 2) - x + 2 = 0

b. 1 - 8x³ = 6x - 12x²

Answer 1

a, 2x(x-2)-x+2=0

<=>2x(x-2)-(x-2)=0

<=>(x-2)(2x-1)=0

=>x-2=0

hoặc 2x-1=0

=>x=2

hoặc x=1/2

b, 1-8x³=6x-12x²

<=>1-8x³-6x+12x²=0

<=>[1³-(2x)³ ] -6x(1-2x)=0

<=>(1-2x)[1+2x+(2x)² ]-6x(1-2x)=0

<=>(1-2x)[1+2x+(2x)²-6x]=0

<=>(1-2x)[1²-2.1.2x+(2x)² ]=0

<=>(1-2x)(1-2x)²=0

<=>(1-2x)³=0

=>1-2x=0

=>2x=1

=>x=1/2

Chúc bn học giỏi nhoa!!!

Answer 2

a)<=>2x(x-2)-(x-2)=0
  <=>(2x-1)(x-2)=0
    +) 2x-1=0
       =>x=1/2
     +)x-2=0
       =>x=2
Vậy x=1/2 hoặc x=2
b) <=>1- (2x)³=6x(1-2x)
 <=>(1-2x)(1+2x+4x²)=6x(1-2x)
<=>(1-2x)(1+2x+4x²)-6x(1-2x)=0
<=>(1-2x)(1+2x+4x2-6x)=0
<=>(1-2x)(1-4x+4x²)=0
<=>(1-2x)(1-2x)²=0
<=>(1-2x)³=0
<=> 1-2x=0
<=>x=1/2
 

Answer 3

mình ko chắn chắn câu b lắm

Answer 4

a. 2x( x - 2 ) -  x + 2 = 0

=>2x( x - 2) -(x - 2) =0

=> ( 2x - 1)( x - 2) =0

=>2x=1 ; x=2

=> x=1/2 ; x=2

b.1 - 8x³ = 6x - 12x²

=> 8x³ -12x² +6x -1 = 0

=>( 2x - 1)³ =0

=>2x = 1

=> x  = 1/2