解:
a-b=m
(a-b)²=m²
a²+b²-2ab=m²
a²+b²=2ab+m²=2x2+m²=m²+4
(a+b)²=(a-b)²+4ab=m²+4x2=m²+8
a-b=m
(a-b)^2=a^2-2ab+b^2=m^2
a^2+b^2=m^2+2ab=m^2+4
(a+b)^2=a^2+b^2+2ab=m^2+4+4=m^2+8
1 a^2+b^2=(a-b)^2+2ab=m^2+2*2=m^2+4
2 (a+b)^2=a^2+b^2+2ab=m^2+4+2*2=m^2+8