问题
选择题
已知-x+2y=5,则5(x-2y)2-3(x-2y)-60的值是( )
A.80
B.10
C.210
D.40
答案
∵-x+2y=5,
∴x-2y=-5,
原式=5(x-2y)2-3(x-2y)-60
=5×(-5)2-3×(-5)-60
=125+15-60
=80.
故本题选A.
已知-x+2y=5,则5(x-2y)2-3(x-2y)-60的值是( )
A.80
B.10
C.210
D.40
∵-x+2y=5,
∴x-2y=-5,
原式=5(x-2y)2-3(x-2y)-60
=5×(-5)2-3×(-5)-60
=125+15-60
=80.
故本题选A.