- FinCloud
-
1.25m^2-49n^2
=(5m)²-(7n)²
=(5m-7n)(5m+7n)
2.4x^2y^2-9a^2b^2
=(2xy)²-(3ab)²
=(2xy-3ab)(2xy+3ab)
- 豆豆staR
-
1.25m^2-49n^2
=(5m+7n)(5m-7n)
2.4x^2y^2-9a^2b^2
=(2xy+3ab)(2xy-3ab)
- 小教板
-
25m^2-49n^2=(5m)^2-(7n)^2=(5m+7n)(5m-7n)
4x^2y^2-9a^2b^2=(2xy)^2-(3ab)^2=(2xy+3ab)(2xy-3ab)
- 我不懂运营
-
a^2-b^2=(a+b)(a-b)
1 a=5m b=7n
25m^2-49n^2=(5m-7n)(5m-7n)
2 a=2xy b=3ab
2.4x^2y^2-9a^2b^2=(2xy+3ab)(2xy-3ab)
- 西柚不是西游
-
1.9(m+n)^2-
4(m-n)^2
=[3(m+n)+2(m-n)][3(m+n)-2(m-n)]
=(5m+n)(m+5n)
2.2x^2-
8x
=2x(x-4)
- 大鱼炖火锅
-
(1-
1/2^2)(1-
1/3^2)(1-
1/4^2)……(1-
1/2007^2)(1-
1/2008^2)
=(1-1/2)(1+1/2)(1-1/3)(1+1/3)……(1-1/2008)(1+1/2008)
=(1/2)(3/2)(3/4)(5/4)……(2007/2008)(2009/2008)
=(1/2)(2009/2008)
=2009/4016
- coco
-
1.25m^2-49n^2
=(5m)²-(7n)²
=(5m-7n)(5m+7n)
2.4x^2y^2-9a^2b^2
=(2xy)²-(3ab)²
=(2xy-3ab)(2xy+3ab)