當2y-x=5時,5(x-2y)2-3(-x+2y)-60=______.

當2y-x=5時,5(x-2y)2-3(-x+2y)-60=______.

∵2y-x=5,∴-x+2y=2y-x=5,x-2y=-(2y-x)=-5,∴5(x-2y)2-3(-x+2y)-60=5×(-5)2-3×5-60=125-15-60=50.故答案是:50.