1.3(2X-1)(X+6)-5(X-3)(X+6) 2.(a-b)(a^2+ab+b^2)

问题描述:

1.3(2X-1)(X+6)-5(X-3)(X+6) 2.(a-b)(a^2+ab+b^2)

3(2X-1)(X+6)-5(X-3)(X+6)
=6x^2+33x-18-5x^2-15x+18
=x^2+18x
(a-b)(a^2+ab+b^2)
=a^3+a^2b+ab^2-a^2b-ab^2-b^3
=a^3-b^3