已知-x+2y=5,那么5(x-2y)2-3(x-2y)-60的值为_.

问题描述:

已知-x+2y=5,那么5(x-2y)2-3(x-2y)-60的值为______.

∵-x+2y=5,
∴x-2y=-5,
∴5(x-2y)2-3(x-2y)-60=5×(-5)2-3×(-5)-60=125+15-60=80.
故答案是80.