\(8x^4y+12x^2y^2+20x^3y^3\)

\(=4x^2y\left(2x^2+3y+5xy^2\right)\)

\(=x^2y\left(8x^2+12y+20xy^3\right)\)

`20x^2y+12x^3`

`=4x^{2}.5y+4x^{2}.3x`

`=4x^2(5y+3x)`

$20x^2y+12x^3$

$ =4x^2.(5y + 3x)$

1. 5x² - 4x

= x(5x - 4)

2. 8x²(x - 3y) - 12x(x - 3y)

= (8x² - 12x)(x - 3y)

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

3. 3(x - y) - 5x(y - x)

= 3(x - y) + 5x(x - y)

= (3 + 5x)(x - y)

1- hay câu 1 vậy bn

=-(y-2x-1)(y²-4xy+y+4x²-2x+1)

\(15\left(x-y\right)-20x\left(y-x\right)=\left(15+20x\right)\left(x-y\right)=5\left(3+4x\right)\left(x-y\right)\)

\(15\left(x-y\right)-20x\left(y-x\right)\)

\(=15\left(x-y\right)+20x\left(x-y\right)\)

\(=5\left(x-y\right)\left(3+4x\right)\)

a,  ( 2x - 1)^2 - (4x + 2) ^2 = ( 2x - 1 - 4x- 2) ( 2x - 1 + 4x + 2) = (-2x-3)(6x+1) = - (2x+3)(6x+1)

b, 8x^3 + 12x^2y + 6xy^2 + y^3 

= (2x)^2 + 3.(2x)^2 . y + 3.2x.y^2 + y^3 

= (2x + y)^3 

a) x² + 6x + 9 = x² + 2 . x . 3 + 3² = (x + 3)²

b) 10x – 25 – x² = -(-10x + 25 +x²) = -(25 – 10x + x²)

                         = -(5² – 2 . 5 . x – x²) = -(5 – x)²

c) 8x³ - 1/8 = (2x)³ – (1/2)³ = (2x - 1/2)[(2x)² + 2x . 12 + (1/2)²]

                    ^{= (2x - 1/2)(4x2 + x + 1/4)} 

d)1/25x² – 64y² = (1/5x)2(1/5x)2- (8y)² = (1/5x + 8y)(1/5x - 8y)