Question

计算 (a的平方+a-1/a+1)-(a的平方-3a+1/a-3)

Answer 1

(a的平方+a-1/a+1)-(a的平方-3a+1/a-3)

=[(a²+a)-1]/(a+1)-[(a²-3a)+1]/(a-3)

=(a²+a)/(a+1)-1/(a+1)-(a²-3a)/(a-3)-1/(a-3)

=a-1/(a+1)-a-1/(a-3)

=-1/(a+1)-1/(a-3)

=[-(a-3)-(a+1)]/(a+1)(a-3)

=(2-2a)/(a²-2a-3)