1
m+1/m=3 (m+1/m)^2=9 m^2+1/m^2=9-2=7 同理m^4+1/m^4=47
2
x^2+y^2+(x-y)^2=2x^2+2y^2-2xy=2(x+y)^2-6xy=2*11^2-6*24=98
3
(x+y)^2+(x-y)^2=2x^2+2y^2=7+3=10
(x+y)^2-(x-y)^2=4xy=7-3=4 xy=1
2x^2+2y^2+xy=11
4
a^2+b^2-2a+6b+10=0 (a-1)^2+(b+3)^3=0 所以a=1 b=-3
(-3)^1=-3
5 (5x-2y)^2
6
25x^2+30xy+k=(5x+m)^2=25x^2+10xm+m^2 m=3y
k=9y^2