a+b/(b-c)(c-a);b+c/(b-a)(a-c);a+c/(a-b)(b-c) 求 通分

(a+b)/(b-c)(c-a)
=-(a+b)/(b-c)(a-c)
=-(a+b)(a-b)/(a-b)(b-c)(a-c)
=-(a²-b²)/(a-b)(b-c)(a-c)
=(b²-a²)/(a-b)(b-c)(a-c)
(b+c)/(b-a)(a-c)
=-(b+c)/(a-b)(a-c)
=-(b+c)(b-c)/(a-b)(b-c)(a-c)
=-(b²-c²)/(a-b)(b-c)(a-c)
=(c²-b²)/(a-b)(b-c)(a-c)
(a+c)/(a-b)(b-c)
=(a+c)(a-c)/(a-b)(b-c)(a-c)
=(a²-c²)/(a-b)(b-c)(a-c)