\(a)\)\(VP=x^3+3x^2+2x\)

\(VP=x\left(x^2+3x+2\right)\)

\(VP=x\left[\left(x^2+x\right)+\left(2x+2\right)\right]\)

\(VP=x\left[x\left(x+1\right)+2\left(x+1\right)\right]\)

\(VP=x\left(x+1\right)\left(x+2\right)\) ( đpcm ) 

Chúc bạn học tốt ~ 

a) x(x+1)(x+2)=(x²+x)(x+2)=x³+2x²+x²+2x=x³+3x²+3x

b)

(3x - 2)(4x - 5) - (2x - 1)(6x + 1) = 0

12x2 - 15x - 8x + 10 - 12x2 - 2x + 6x + 1 = 0

- 19x = - 11

x = 11/19

\(a^3+b^3+c^3-3abc=\left(a+b\right)^3+c^3-3ab\left(a+b+c\right)\)

\(=\left(a+b+c\right)\left[\left(a+b\right)^2-\left(a+b\right)c+c^2\right]-3ab\left(a+b+c\right)\)

\(=\left(a+b+c\right)\left(a^2+b^2+c^2-ab-bc-ca\right)\)

b,

Ta có:

\(\left(a+b+c\right)^3=0\Rightarrow a^3+b^3+c^3+3\left(a+b\right)\left(b+c\right)\left(c+a\right)=0\)

\(\Rightarrow a^3+b^3+c^3-3.\left(-c\right)\left(-a\right)\left(-b\right)=0\)

Những CTHH viết sai là: MgCl, KO, NaCO₃;

Sửa lại cho đúng: MgCl₂, K₂O, Na₂CO₃.

vào Vietjack mà tra bn ơi.

75781378774

= 75781378774 cho mk nha bn

a) x² + 5x + 4

= x² + x + 4x + 4 

= x (x+1) + 4 (x+1)

= (x+1) ( x+4)

c) x² - 7x + 12

= x² - 3x - 4x +12

= x(x-3) - 4(x-3)

= (x-3)( x-4)

m) \(5x^2+6x+1\)

\(=5x^2+5x+x+1\)

\(=5x\left(x+1\right)+\left(x+1\right)\)

\(=\left(5x+1\right)\left(x+1\right)\)