利用乘法公式计算 (9 17:46:38)(a2-ab-b2)(a2+ab-b2)(x2y+2xy2)(3x+6y)41005-22009 41005-22007

Question

利用乘法公式计算 (9 17:46:38)
(a2-ab-b2)(a2+ab-b2)
(x2y+2xy2)(3x+6y)
41005-22009
                         
41005-22007
 

Answer 1

(a^2-ab-b^2)(a^2+ab-b^2)
=(a^2-b^2-ab)(a^2-b^2+ab)
=(a^2-b^2)^2-(ab)^2
=a^2-2a^2b^2+b^4-a^2b^2
=a^4-3a^2b^2+b^4
(x^2y+2xy^2)(3x+6y)
=2xy(x+2y)(x+2y)
=2xy(x^2+4xy+4y^2)
=2x^3y+8x^y^2+8xy^3