(x²+2x)²+2x²+4x+1
=(x²+2x)²+2(x²+2x)+1
=(x²+2x+1)²
=(x+1)
ab(x²+1)+x(a²+b²)吧,
=abx²+ab+x(a²+b²)
=abx²+x(a²+b²)+ab
=(ax+b)(bx+a)
(x²+2x)²+2x²+4x+1
=(x²+2x)²+2(x²+2x)+1
=(x²+2x+1)²
=(x+1)
ab(x²+1)+x(a²+b²)吧,
=abx²+ab+x(a²+b²)
=abx²+x(a²+b²)+ab
=(ax+b)(bx+a)