明代内阁和清代军机处的共同之处是(     )

Sydney Tower
Address: 100 Market St, Sydney
Phone: 02 9333 9222
Fax: 02 9333 9203
Open time: 9:00 a.m. t0 10:30 p.m. (Saturdays to 11:30 pm)
Ticket: $60 (for an adult) $30 (for a child)
Website: www.sydneytower.com.au
How to get there: train to Town Hall Station and a short walk along Market Street
How to book tickets: by phone/fax or through the web
Attractions: Sydney’s best views are just the beginning! Sydney Tower takes you to the highest point
above Sydney for exciting 360° view of our beautiful city.

已知二次函数y=ax²+bx+c（a≠0）的图象如图所示，有下列结论：①abc＞0；②a+b+c＞0；③a-b+c＜0；其中正确的结论有（　　）