Let a,b and c be rationd numbers and b=5/12-5/13a,c=5/13-5/12a,then aa-bb=cc=(

题目

Let a,b and c be rationd numbers and b=5/12-5/13a,c=5/13-5/12a,then aa-bb=cc=(

答案

让A ,B和C是rationd号码和B = 5/12-5/13a和c = 5/13-5/12a ,然后机管局一BB =消委会= （）