分解因式9（x+y）²-（x-y）²=（）（）.

分解因式9（x+y）²-（x-y）²=（）（）.
分解因式9（x+y）²-（x-y）²=（）（）.

分解因式9（x+y）²-（x-y）²=（）（）.
9(x+y)²-4(x-y)²
=[3(x+y)]²-[2(x-y)]²
=[3(x+y)+2(x-y)][3(x+y)-2(x-y)]
=(5x+y)(x+5y)
3x²-12
=3(x²-4)
=3(x+2)(x-2)
x^5 -x³
=x³(x²-1)
=x³(x+1)(x-1)
-5a³b+20ab³
=-5ab(a²-4b²)
=-5ab(a+2b)(a-2b)

都用平方差公式就行了，后面三个先提取公因式再用

3(x+y-x+y)*3(x+y+x-y)
=3y*3x
=9xy

9(x+y)^2 - (x-y)^2=4(2x+ y)(x+2y)
9(x+y)^2 - 4(x-y)^2=(5x+ y)(x+5y)
3x^2 -12 = 3(x+2)(x-2)
x^5 - x^3 = x^3(x + 1)(x - 1)
-5a^3b + 20ab^3 = -5ab(a + 2b)( a - 2b)