①(x+3y)^2(x-3y)^2②(0.5m+n)(0.5m-n)(0.25m^2-n^2)小数为分数（分数不好打）
问题描述：
①(x+3y)^2(x-3y)^2
②(0.5m+n)(0.5m-n)(0.25m^2-n^2)
小数为分数（分数不好打）
答
(x+3y)^2(x-3y)^2=(x^2-9y^2)^2
(0.5m+n)(0.5m-n)(0.25m^2-n^2) =(0.25m^2-n^2))(0.25m^2-n^2)=(0.25m^2-n^2)^2
答
①(x+3y)^2(x-3y)^2=(x+3y)(x-3y)(x+3y)(x-3y)=(x^2-9y^2)^2=x^4-18x^2y^2+81y^4
②(0.5m+n)(0.5m-n)(0.25m^2-n^2)=(0.5m+n)(0.5m-n)(0.5m+n)(0.5m-n)=(0.25m^2-n^2)(0.25m^2-n^2)=0.0625m^4-0.5m^2n^2+n^4
答
。。。。题呢
答
你让人空想呀
答
①(x+3y)^2(x-3y)^2
=（(x+3y)(x-3y)）^2
=(x^2-9y^2)^2
=x^4+81y^4-18x^2y^2
②(0.5m+n)(0.5m-n)(0.25m^2-n^2)
=(0.25m^2-n^2)(0.25m^2-n^2)
=0.625m^4-0.5m^2n^2+n^4
答
1、原式=[(x+3y)(x-3y)]^2=(x^2-9y^2)^2=x^4-18x^2y^2+81y^4
2、原式=(0.25m^2-n^2)(0.25m^2-n^2)=m^4/16-0.5m^2n^2+n^4