①3x＾2+2xy
=x(3x+2y)
②4a＾2x＾2-16a＾2y＾2
=4a^2(x^2-4y^2)
=4a^2(x-2y)(x+2y)
③(x-y)＾n+2-(x-y)＾n
=(x-y)＾n(x^2-1)
=(x-y)＾n(x-1)(x+1)
④a＾2+36分之一b＾2+3分之一ab
=1/36(36a^2+b^2+12ab)
=1/36*(6a+b)^2
=(6a+b)^2/36