Question

（a＋b）/（a*2+b*2)的公因式

Answer 1

（a＋b）/（a^2+b^2)没有公因式

(x^2+x-2)/(x^2-1)

=(x-1)(x+2)/[(x+1)(x-1)]

公因式是x-1

(x^2+x-2)/(x^2-1)

=(x+2)/(x+1)