Question

Bài1: Viết các đơn thức sau thành tích:

a) x³ + 8y³

b) a^{6 _} b³

^c) 8y^{3 _} 125

d) 8z³ +27

Answer 1

a ) \(x^3+8y^3=x^3+\left(2y\right)^3=\left(x+2y\right)\left(x^2-2xy+4y^2\right)\)

b ) \(a^6-b^3=\left(a^2\right)^3-b^3=\left(a^2-b\right)\left(a^4+a^2b+b^2\right)\)

c ) \(8y^3-125=\left(2y\right)^3-5^3=\left(2y-5\right)\left(4y^2+10y+25\right)\)

d ) \(8z^3+27=\left(2z\right)^3+3^3=\left(2z+3\right)\left(4z^2-6z+9\right)\)

Answer 2

a) x³ + 8y³ = x³ + (2y)³ = (x+2y)(x²+2xy+4y²)

b) a⁶ - b³ = (a²)³ - b³ = (a²-b)(a⁴ + a²b + b²)

c) 8y³ - 125 = (2y)³ - 5³ = (2y - 5)(4y² + 10y + 25)

d) 8x³ + 27 = (2z)³ + 3³ = (2z + 3)(4z² - 6x + 9)

Answer 3

a) \(x^3+8y^3\)

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

\(=\left[x+2y\right]\left[x^2-x.2y+\left(2y\right)^2\right]\)

\(=\left[x^3+8y^3\right]\left[x^2-2xy+4y^2\right]\)