ax^4-9ay^4
问题描述：
ax^4-9ay^4
答
36m??n??-(9m??+n??)??=(6mn)??-(9m??+n??)??【利用平方差公式】=(6mn-9m??-n??)(6mn+9m??+n??)=-(9m??+n??-6mn)(9m??+6mn+n??)=-(3m-n)??(3m+n)??
答
ax^4-9ay^4
=a(x^4-9y^4)
=a[(x^2)^2-(3y^2)^2]
=a(x^2+3y^2)(x^2-3y^2)
=a(x^2+3y^2)(x+√3y)(x-√3y) .