\(x^3-8=x^3-2^3=\left(x-2\right)\left(x^2+2x+4\right)\)
\(x^3-8y^3=x^3-\left(2y\right)^3=\left(x-2y\right)\left[x^2+x\left(2y\right)+\left(2y\right)^2\right]=\left(x-2y\right)\left(x^2+2xy+4y^2\right)\)
Sai thì chịu
\(x^3-8=x^3-2^3=\left(x-2\right)\left(x^2+2x+4\right)\)
\(x^3-8y^3=x^3-\left(2y\right)^3=\left(x-2y\right)\left(x^2+2xy+4y^2\right)\)
a) \(x^3-8
\)
\(=x^3-2^3\)
\(=\left(x-2\right)\left(x^2+2x+4\right)\)
b) \(x^3-8y^3
\)
\(=x^3-\left(2y\right)^3\)
\(=\left(x-2y\right)\left(x^2+2xy+4y^2\right)\)