A:970
B:680
C:640
D:170
幂函数y=(m2﹣2m﹣2)•xm﹣2,当x∈(0,+∞)时为减函数,则实数m的值为( )
一双运动鞋原价100元.现在以八折售出,这双运动鞋的实际售价是____元.
—Thanks! But I__________ it for several times.