1.已知m^2-5m-1=0,则2m^2-5m+m^-2=?2.已知非负数a.b.c满足条件a+b=7,c-a=5,设S=a+b+c的最大值为m,最小...1.已知m^2-5m-1=0,则2m^2-5m+m^-2=?2.已知非负数a.b.c满足条件a+b=7,c-a=5,设S=a+b+c的最大值为m,最小值为n,则m-n的

Question

1.已知m^2-5m-1=0,则2m^2-5m+m^-2=?2.已知非负数a.b.c满足条件a+b=7,c-a=5,设S=a+b+c的最大值为m,最小...
1.已知m^2-5m-1=0,则2m^2-5m+m^-2=?2.已知非负数a.b.c满足条件a+b=7,c-a=5,设S=a+b+c的最大值为m,最小值为n,则m-n的值为?

Answer 1

2、由a+b=7,c-a=5可得b+c=12
又因为a.b.c为非负数,所以0