3ax^2-12ay^2

问题描述:

3ax^2-12ay^2
0.49m^2-25n^2

3ax^2-12ay^2=3a(x^2-4y^2)
=3a(x+2y)(x-2y)
0.49m^2-25n^2=(0.7m+5n)(0.7m-5n)