Question

初中因式分解

①：a^2-b^2-4a+4b
②：x^2·(x-y)+(y-x)
③：2a(x^2+1)^2-2ax^2
急急急急~~

Answer 1

①：a^2-b^2-4a+4b=(a+b)(a-b)-4(a-b)=(a+b-4)(a-b)
②：x^2·(x-y)+(y-x)=x^2·(x-y)-(x-y)=(x²-1)(x-y)=(x+1)(x-1)(x-y)
③：2a(x^2+1)^2-2ax^2=2a[(x^2+1)^2-x^2]=2a[(x^2+1)+x][(x^2+1)-x]=2a(x^2+x+1)(x^2-x+1)