Question

若a/(a-b)=1/2,则(3a²-5ab+2b²)/(2a²+3ab-6b²

Answer 1

若a/(a-b)=1/2,

2a=a-b;a+b=0;a/b=-1;则(3a²-5ab+2b²)/(2a²+3ab-6b²)=(3a/b-5+2b/a)/(2a/b+3-6b/a)=(3×(-1)-5-2)/(-2+3+6)=-10/(7)=-10/7;