a^4＋a^2—a·b^3—ab=a(a³-b³)+a(a-b)=a(a-b)(a²+ab+b²)+a(a-b)=a(a-b)(a²+ab+b²+1)
xy—xz—y^2+2yz=x(y-z)-y(y-z)=(y-z)(x-y)
x^2—xy+4x—4y=x(x-y)+4(x-y)=(x-y)(x+4)
x^3+3·x^2—4x—12=x²(x+3)-4(x+3)=(x+3)(x²-4)=(x+3)(x-2)(x+2)
x^3+6x^2+11x+6=x³+6x²+9x+2x+6=(x+3)²+2(x+3)=(x+3)(x+5)
2·x(^3n) — 12·X(^2n ）· y（^2）+18·x(^n) · y(^4)=
=2x^n(x^2n-6x^ny^2+9y^4
=2x^n(x^n-3y²)²
（ax+by）^2+（ay—bx）^2+c^2 · x^2+c^2 · y^2
=a²x²+2abxy+b²y²+a²y²-2abxy+b²x²+c²x²+c²y²
=a²x²+b²y²+a²y²+b²x²+c²x²+c²y²
=a²(x²+y²)+b²(x²+y²)+c²(x²+y²)
=(x²+y²)(a²+b²+c²)
（x^2+y^2）^3+（z^2—x^2）^3—（y^2+z^2）^3
=(x²+y²+z²-x²)[(x²+y²)²-(x²+y²)(z²-x²)+(z²-x²)²]-(y²+z²)³
=(y²+z²)(x^4+2x²y²+y^4-x²z²-y²z²+x^4+x²y²+z^4-2x²z²+x^4-y^4-2y²z²-z^4)
=(y²+z²)(3x^4+3x²y²-3x²z²-3y²z²)
=3(y²+z²)(x^4+x²y²-x²z²-y²z²)
=3(y²+z²)[x²(x²+y²)-z²(x²+y²)]
=3(y²+z²)(x²+y²)(x²-z²)
x^6+64·y^6+12x（^2）y(^2)—1不好意思，第二題：xy—xz—y^2+2yz后面再減個(gè)z^2變成 xy—xz—y^2+2yz—z^2別的你確定都對(duì)么？給我一個(gè)肯定的“對(duì)！""或者“拿不準(zhǔn)！”肯定對(duì)，你看我的等級(jí)就知道了，我本來就是老師呃，老師啊。。謝謝您，，第二題幫我再算一下，最后一題怎么了？？xy—xz—y^2+2yz—z^2=x(y-z)-(y-z)²=(y-z)(x-y+z)最后一題題目有問題