化简求值：[(3m/(m+2)-m/(m-2)]/[(2m)/m^2-4)],其中m=2/3

题目

化简求值：[(3m/(m+2)-m/(m-2)]/[(2m)/m^2-4)],其中m=2/3
快!

答案

原式={[3m(m-2)-m(m+2)]/(m+2)(m-2)}/[2m/(m²-4)]
=[(3m²-6m-m²-2m)/(m²-4)]/[2m/(m²-4)]
=(2m²-8m)/2m
=2m(m-4)/2m
=m-4
=2/3-4
=-10/3