1.1/4+a^2+a^4
问题描述：
1.1/4+a^2+a^4
2.(1/36a-1/3)a+1
3.(x^2-2xy+y^2)+(-2x+2y)+1
答
1.(a^2+1/2)^2
2.(1/36a-1/3)a+1 =(1/6*a-1)^2
3.(x^2-2xy+y^2)+(-2x+2y)+1
=(x-y)^2-2(x-y)+1
=(x-y-1)^2
看懂了吗?