Question

计算。﹙2x＋3y﹚﹙2x－3y﹚－﹙x＋2y﹚﹙x－2y﹚.

[﹙2x＋y﹚²－﹙2x＋y﹚﹙2x－y﹚]÷2x－y.

Answer 1

﹙2x＋3y﹚﹙2x－3y﹚－﹙x＋2y﹚﹙x－2y﹚.
=4X²-9y²-x²+4y²
=3x²-5y²

[﹙2x＋y﹚²－﹙2x＋y﹚﹙2x－y﹚]÷(2x－y)
=(4x²+4xy+y²-4x²+y²)÷(2x-y)
=(4xy+2y²)/(2x-y)

Answer 2

1原式=4x²-9y²-x²+4y²
=3x²-5y²
(=(√3x+√5y)(√3x-√5y))

2原式=(2x+y)(2x+y-2x+y)/2x-y
=2y(2x+y)/2x-y
=y+y²/2x-y
=y²/2x