Answer: y=0,5x²-x-1,5.
Step-by-step explanation:

We summarize (1) and (3):

Substitute b=-1 into (2):

From (5) subtract (4):

Substitute a=0,5 into (4):

Hense:
y=0,5x²-x-1,5.
Answer:
12x+24
Step-by-step explanation:
Answer:
34 classes
Step-by-step explanation:
First, subract 180 from 1200. You should get 1020. then do 1020/30. So 34 classes can watch the performance of 180 students.
65/3=21 with 2 leftover
(2/3)/3 or 2/3•1/3 = 2/9
so either they didn’t get to share or each got 2/9 of the leftovers