首页 > 留学知识库

问题: 初中计算~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

1.(64/169)a^4- 289 b^2 c^6

2.25(x+y)^2-9(x-y)^2

解答:

是因式分解吧!
1.(64/169)a^4- 289 b^2 c^6
=[(8/13)*a^2+17bc^3][(8/13)a^2-17bc^3]

2.25(x+y)^2-9(x-y)^2
=(5x+5y+3x-3y)*(5x+5y-3x+3y)
=4(4x+y)*(x+4y)