✔ 最佳答案
x²-4m²n²
=(x)^2-(2mn)^2
=(x-2mn)(x+2mn)
(用了恆等式(a²-b²=(a+b)(a-b)))
x^8-16
=(x^4)²-4²
=(x^4-4)(x^4+4)
=(x²-2)(x²+2)(x^4+4)
4a²-4a+1
=(2a)²-2(2a)+1
=(2a-1)²
25y²-10y+1
=(5y)²-2(5y)+1²-----because1=1²=1³=1^n
=(5y-1)²
4x²-44x+121
=(2x)²-2(2x)(11)+11²
2x↘-11
2x↗-11
----------------
-22x-22x=44x=2(2x)(11)
=(2x-11)²
16x²-24x+9
=(4x)²-2(4x)(3)+3²
4x↘-3
4x↗-3
-------------
-12x-12x=-24x=-2(4x)(3)
=(4x-3)²
4a²+12ab+9b²
=(2a)²+2(2a)(3b)+(3b)²
2a↘3b
2a↗3b
----------
6b+6b=2(2a)(3b)
=(2a+3b)²
20m²+20mn+5n²
=5(4m²+4mn+n²)
=5[(2m)²+2(2m)(n)+n²)
2m↘n
2m↗n
---------
2mn+2mn=2(2m)(n)
=5(2m+n)²
8a²+40ab+50b²
=2(4a²+20ab+25b²)
=2[(2a)²+2(2a)(5b)+(5b)²]
2a↘5b
2a↗5b
---------
10ab+10ab=2(2a)(5b)
=2(2a+5b)²