a(1-a)-(a-1)的平方
=-a(a-1)-(a-1)²
= -(a-1)(a+a-1)
= -(a-1)(2a -1)
(x²+2x)²+2(x²+2x)+1
= (x²+2x +1)²
-ab(a-b)²+a(b-a)²
= -a(a-b)² (b -1)
a(1-a)-(a-1)的平方
=-a(a-1)-(a-1)²
= -(a-1)(a+a-1)
= -(a-1)(2a -1)
(x²+2x)²+2(x²+2x)+1
= (x²+2x +1)²
-ab(a-b)²+a(b-a)²
= -a(a-b)² (b -1)