Question

数学问题 初二因式分解的 速度在线等

已知a+b=1,ab=1/2,利用因式分解求a(a+b)(a-b)-a(a+b)^2的值

Answer 1

a(a+b)(a-b)-a(a+b)^2=a(a+b)(2b)=2(a+b)ab=1

Answer 2

a(a+b)(a-b)-a(a+b)^2=a(a+b)[(a-b)-(a+b)]=a(a+b)[(a-b)-(a+b)]=a(a+b)(-2b)=-2ab(a+b)=-1/2

Answer 3

a(a+b)(a-b)-a(a+b)^2=a(a+b)(a-b-a-b)=-2ab(a+b)=-2*1/2*1=-1

Answer 4

a(a+b)(a-b)-a(a+b)^2=a(a^2-b^2)-a(a^2+2ab+b^2)=-2ab^2-2ba^2=-2ab(a+b)=-1