[x+p]²-[x+q]² =?【2x+y】²-【x+2y】²=?

[x+p]²-[x+q]²
=[(x+p)+(x+q)][(x+p)-(x+q)]
=(x+p+x+q)(x+p-x-q)
=(2x+p+q)(p-q)
【2x+y】²-【x+2y】²
=[(2x+y)+(x+2y)][(2x+y)-(x+2y)]
=(3x+3y)(x-y)
=3(x+y)(x-y)
16【x+y】²-9【x-y】²
=[4(x+y)]²-[3(x-y)]²
=[4(x+y)+3(x-y)][4(x+y)-3(x-y)]
=(7x+y)(x+7y)
4【2x-3】²-x²
=[2(2x-3)]²-x²
=[2(2x-3)+x][2(2x-3)-x]
=(5x-6)(3x-6)
=3(5x-6)(x-2)

你还真没理解啊，看一下（1）的过程
把x+p看作a，x+q看作b
代入a²-b²=(a+b)(a-b)得[(x+p)+(x+q)]*[(x+p)-(x+q)]=(2x+p+q)(p-q)
（2）把2x+y看作a，x+2y看作b
（3）(4x+4y)²-(3x-3y)²，把4x+4y看作a，3x-3y看作b
（4）把2x...