左边=4x/(x²-4）右边=a/(x+2)-b/(x-2)=[a(x-2)-b(x+2)]/(x+2)(x-2)=[(a-b)x-2(a+b)]/(x²-4）左边=右边所以4x=(a-b)x-2(a+b)]所以a-b=4,a+b=0解得a=2,b=-2所以a²+b²=8