a) 7x³ - 5x² 

= x²( 7x - 5 )

b) x² - 10x + 25

= x² - 2.5.x + 5²

= ( x - 5 )²

a, 7x³-5x²

=x²(7x-5)

b, x²-10x+25

=x²-2.x.5+5²

=(x-5)²

Ta có:\(7x^3-5x^2=x^2\left(7x-5\right)\)

          \(x^2-10x+25=\left(x-5\right)^2\)

ko pt dc nhé bạn

\(2\left(x-1\right)^3-5\left(x-1\right)^2-\left(x-1\right)=\left(x-1\right)\left[2\left(x-1\right)^2-5\left(x-1\right)-1\right]=\left(x-1\right)\left(2\left(x^2-2x+1\right)-5x+5-1\right)=\left(x-1\right)\left(2x^2-4x+2-5x+5-1\right)=\left(x-1\right)\left(2x^2-9x+6\right)\)

\(2\left(x-1\right)^3-5\left(x-1\right)^2-\left(x-1\right)\)

\(=\left(x-1\right)\left[2\left(x-1\right)^2-5\left(x-1\right)-1\right]\)

\(=\left(x-1\right)\left[2\left(x^2-2x+1\right)-5\left(x-1\right)-1\right]\)

\(=\left(x-1\right)\left(2x^2-4x+2-5x+5-1\right)\)

\(=\left(x-1\right)\left(2x^2-9x+6\right)\)

\(2\left(x-1\right)^3-5\left(x-1\right)^2-\left(x-1\right)\)

\(=\left(x-1\right)\left(2x^2-4x+2-5x+5-1\right)\)

\(=\left(x-1\right)\left(2x^2-9x+6\right)\)

Ta có `:`

`x^3 - 7x-6`

`= x^3 - 9x + 2x - 6`

`= x( x^2 - 9 ) + 2( x-3 )`

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

`= [ x( x + 3 )+2]( x-3 )`

`= ( x^2 + 3x + 2 )( x-3 )`

`= ( x^2 + 2x + x + 2 )( x-3 )`

`= [x( x+2 ) + ( x + 2 )]( x-3 )`

`= ( x+1)(x+2)(x-3)`  

hãy giúp mình đi ạ `bb!` 

P(x)=x(x+3)(x+1)(x+2)+1

P(x)=(x²+3x)(x²+3x+2)+1

Đặt x²+3x=a

Ta có:

P(x)=a(a+2)+1

P(x)=a²+2a+1

P(x)=(a+1)²

Vậy P(x)=(x²+3x)²

x³ + 7x - 6

= x³ - x - 6x - 6

= x³ - x - 6 (x+1)

= x (x² - 1) - 6 (x+1)

= (x + 1) ( x (x - 1) - 6 )

= ( x + 1) ((x² - x - 6))

= (x + 1) ((x² + 2 - 3 - 6))

= (x + 1) (x(x +2) - 3 ( x + 2))

= (x + 1)(x + 2)(x + 3)