Question

Viết các biểu thức sau dưới dạng tích.

A)x³+27

B)x³-1/8

C)8x³+y³

D)8x³-27y³

 

Answer 1

A) \(x^3+27\)

\(=x^3+3^3\)

\(=\left(x+3\right)\left(x^2-3x+9\right)\)

B) \(x^3-\dfrac{1}{8}\)

\(=x^3-\left(\dfrac{1}{2}\right)^3\)

\(=\left(x-\dfrac{1}{2}\right)\left(x^2+\dfrac{1}{2}x+\dfrac{1}{4}\right)\)

C) \(8x^3+y^3\)

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

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

D) \(8x^3-27y^3\)

\(=\left(2x\right)^3-\left(3y\right)^3\)

\(=\left(2x-3y\right)\left(4x^2+6xy+9y^2\right)\)

Answer 2

a)\(\left(x+3\right)\left(x^2-3x+9\right)\)

b)\(\left(x-\dfrac{1}{2}\right)\left(x^2+\dfrac{1}{2}x+\dfrac{1}{4}\right)\)

c)\(\left(2x+y\right)\left(4x^2-2xy+y^2\right)\)

d)\(\left(2x-3y\right)\left(4x^2+6xy+9y^2\right)\)