A:x﹣3=2x
B:x2﹣2=0
C:x2﹣2y=1
D:1x+1=2x
已知三角形ABC中,三边长分别是a,b,c,面积S=a2﹣(b﹣c)2,b+c=8,则S的最大值是____
Travelling to London
We think ⑴ is the best season to visit England.
We did most of our sightseeing(观光) ⑵ .
The best part of the trip was going to the theatre.
We don't think the English food is very ⑶ .
己知下列变化过程中,有一个RxO72﹣离子反应时,反应就转移6个电子,
RxO72﹣+ Fe2++ H+= R3++ Fe3++ H2O