Question

1、m-n=2,mn=1,则m^4 n^2+m^2 n^4的值是（） 2、分解因式：(x^2-xy)^2-(xy-y^2

Answer 1

(m+n)^2=m^2+n^2-2mn=4;

2mn=2

m^2+n^2=6

m^4 n^2+m^2 n^4=m^2n^2(m^2+n^2)=1×6=6

剩下的有些题目看不清楚