﹙1﹚x²-4y²+x-2y =(x²-4y²)+(x-2y )
=(x+2y )(x-2y )+(x-2y )
=(x-2y )(x+2y +1)
﹙2﹚4a²-﹙a²+1﹚²
=(2a)²-﹙a²+1﹚²
=(2a+a²+1)(2a-a²-1)
=(a²+2a+1)(-a²+2a-1)
=-(a+1)²(a²-2a+1)
=-(a+1)²(a-1)²
﹙1﹚x²-4y²+x-2y =(x²-4y²)+(x-2y )
=(x+2y )(x-2y )+(x-2y )
=(x-2y )(x+2y +1)
﹙2﹚4a²-﹙a²+1﹚²
=(2a)²-﹙a²+1﹚²
=(2a+a²+1)(2a-a²-1)
=(a²+2a+1)(-a²+2a-1)
=-(a+1)²(a²-2a+1)
=-(a+1)²(a-1)²