=(x+2)(x+5)(x+3)(x+4)-24

=(x²+2x+5x+10)(x²+3x+4x+12)-24

=((x²+7x+11)-1)((x²+7x+11)+1)-24

=(x²+7x+11)²-1²-24

=(x²+7x+11)²-25

=(x²+7x+11)²-5²

=(x²+7x+11-5)(x²+7x+11+5)

=(x²+7x+6)(x²+7x+16)

=(x²+x+6+6x)(x²+7x+16)

=(x(x+1)+6(x+1))(x²+7x+16)

=(x+6)(x+1)(x²+7x+16)

Tick cho mình nhé

(x² + 2.x.3 + 3² - 1).(x² + 2.x.4 + 16 - 1) - 24

=[(x+3)² - 1]. [(x+4)²-1] -24

=(x+3+1)(x+3-1)(x+4+1)(x+4-1) - 24

=(x+4)(x+2)(x+5)(x-3) - 24

(x²+6x+8)(x²+8x+15)-24

<=>(x²+4x+2x+8)(x²+5x+3x+15)-24

<=> [x(x+4)+2(x+4)][x(x+5)+3(x+5)]-24

<=> (x+4)(x+2)(x+5)(x+3)-24

<=> (x+4)(x+3)(x+2)(x+5)-24

<=>(x²+7x+12)(x²+7x+10)

đặt t=x²+7x+11 ta có:

(t-1)(t+1)-24

<=> t²-1-24

<=>t²-25

<=>(t-5)(t+5)

thay t=x²+7x+11 vào ta có:

(x²+7x+11-5)(x²+7x+11+5)

<=>(x²+7x+6)(x²+7x+16)

Câu a :

\(x^2-3x+2\)

\(=x^2-x-2x+2\)

\(=\left(x^2-x\right)-\left(2x-2\right)\)

\(=x\left(x-1\right)-2\left(x-1\right)\)

\(=\left(x-1\right)\left(x-2\right)\)

2x³ - 8x² + 8x

= 2x.(x² - 4x + 4)

= 2x.(x - 2)²

2x² - 3x - 5

= 2x² + 2x - 5x - 5

= (2x² + 2x) - (5x + 5)

= 2x.(x + 1) - 5.(x + 1)

= (x + 1).(2x - 5)

x²y - x³ - 9y + 9x

= (x²y - x³) - (9y - 9x)

= x².(y - x) - 9.(y - x)

= (y - x).(x² - 9)

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