Chuyển các câu sau sang câu chủ động:
1. It was decided that their marriage would be organized in December.
-> ...................................................
2. I had been given a card to the club and in the afternoon it was used by me to go there to play bridge.
-> ...........................................................
3. You will be given new instructions before you leave.
-> ..................................................

Cho a+b+c = 0. Tính a^3+b^3+c(a^2+b^2)-abc