1、a²-b²+2a+1
=(a²+2a+1)-b²
=(a+1)²-b²
=(a+b+1)(a-b+1)
2、(x²+3x)²-8(x²+3x)-20
=(x²+3x-10)(x²+3x+2)(把x²+3x看成一个整体再十字相乘)
=(x+5)(x-2)(x+1)(x+2)
1、a²-b²+2a+1
=(a²+2a+1)-b²
=(a+1)²-b²
=(a+b+1)(a-b+1)
2、(x²+3x)²-8(x²+3x)-20
=(x²+3x-10)(x²+3x+2)(把x²+3x看成一个整体再十字相乘)
=(x+5)(x-2)(x+1)(x+2)