Question

计算：（1）（a-2)(a^2+2a+4)= (2x-y)(4x^2+2xy+y^2)=

Answer 1

（1）（a-2)(a^2+2a+4)= a³-8

(2x-y)(4x^2+2xy+y^2)=8x³-y³

(2)这是立方差公式a³-b³=(a-b)(a²+ab+b²)

(3)

（3x-2y)（9x^2+6xy+4y^2)=27x³-8y³

(2m-3)(4m^2+( 6m )+9)=8m³-27

(4)

27m^3-8=(3m-2)(9m²+6m+4)