1.如果实数m、n满足（m^2+n^2)^2-3=2(m^2+n^2),
（m^2+n^2)^2-3-2(m^2+n^2)=0
(m^2+n^2-3)(m^2+n^2+1)=0
m^2+n^2>=0
m^2+n^2+1>=1
m^2+n^2=3
2.解关于x的一元二次方程：x^2-(m^2+5)x+2(m^2+3)=0
x^2-(m^2+5)x+2(m^2+3)=(x-2)(x-m²-3)=0
x1=2
x2=m²+3