已知a/x+3与b/x-3的和等于4x/x^-9,求常数a、b的值
问题描述：
已知a/x+3与b/x-3的和等于4x/x^-9,求常数a、b的值
答
(a/x+3)+(b/x-3) =[a(x-3)+b(x+3)]/(x^-9) =[ax-3a+bx+3b]/x^-9 =[x(a+b)+(3b-3a)]/x^-9 =4x/x^-9 a+b=4 3b-3a=0 a=2 b=2