Question

[(c²+ac)+(ab+bc)][(c²-ac)+(ab-bc)如何转化到(a+c)(c+b)(c-a)(c-b)?

Answer 1

[(c²+ac)+(ab+bc)][(c²-ac)+(ab-bc)]

=[c(c+a)+b(a+c)][c(c-a)-b(c-a)]

=(c+a)(c+b)(c-a)(c-b)