\(x^3-4^3=\left(x-4\right)\left(x^2+4x+16\right)\)

x^3-64=x^3-4^3=(x-4)^3=x^3-3x^2.4+3x.4^2-4^3=x^3-12x^2+48x-64

\(x^3-64=x^3-4^3=\left(x-4\right)\left(x^2+4x+16\right)\)

\(x^3-64x\)

\(=x\left(x^2-64\right)=x\left(x^2-8^2\right)\)

\(=x\left(x-8\right)\left(x+8\right)\)

\(=x^3+9x^2+27x+27\)

a: \(=x^2-12x+36\)

b: \(=x^3+9x^2+27x+27\)

A.x=6

b.x=-3

x³+8y³=x³+(2y)³=(x+2y)(x²-2xy+4y²)

P/s: Mình nghĩ vậy đó.

(x-2)^3=x³-6x²+12x-8

\(\left(x-2\right)^3=x^3-3\cdot x^2\cdot2+3\cdot x\cdot2^2-2^3\)

\(=x^3-6x^2+12x-8\)

\(\left(x-2\right)^3\)
\(=x^3-3.x^2.2+3.x.2^2-2^3\)
\(=x^3-6x^2+12x-8\)

\(1,=x\left(2x+3\right)-\left(2x+3\right)=2x^2+3x-2x-3=2x^2+x-3\\ 2,=\left(2x\right)^2-2.2.x.1+1^2=4x^2-4x+1\)

1. =2x²-2x+3x-3

2. (2x)²-2.2x.1+1²

=4x²-4x+1

a) \(\left(2x+1\right)^3\)

\(=\left(2x\right)^3+3.\left(2x\right)^2.1+3.2x.1+1\)

\(=8x^3+12x^2+6x+1\)

b) \(\left(x-3\right)^3\)

\(=x^3-3.x^2.3+3.x.3^2-3^3\)

\(=x^3-9x^2+27x-27\)

Bài 2: 

a: \(x^3+15x^2+75x+125=\left(x+5\right)^3\)

b: \(1-15y+75y^2-125y^3=\left(1-5y\right)^3\)

c: \(8x^3+4x^2y+\dfrac{3}{2}xy^2+8y^3=\left(2x+2y\right)^3\)