已知-x+2y=5,那么5(x一2y)∧2一3(x一2y)一60的值为( ) A
问题描述:
已知-x+2y=5,那么5(x一2y)∧2一3(x一2y)一60的值为( ) A
已知-x+2y=5,那么5(x一2y)∧2一3(x一2y)一60的值为( ) A -17 B -7 C -3 D 7
答
-x+2y=5
∴x-2y=-5
5(x一2y)∧2一3(x一2y)一60
=5×(-5)^2-3×(-5)-60
=125+15-60
=80这是一道选择题,答案中没80说明题目错了呀