When b=0
f(x)=ax^2+c
test each
A. with x^2-1, A is false
B. with -x^2-1, B is false
C. cannot find contradiction
D. the axis is actually x=0, 0 is nithere positive nor negative, false
answer is C
From the table we can see:
Number of songs: Cost:
0 $ 0
1 $1.25
2 $2.50
3 $3.75
4 $5.00
Therefore the rate of change is: (2.50 - 1.25) / ( 2 - 1 ) = $1.25
Answer:
It means that : C. The cost increases $1.25 for each additional song that is downloaded.
check the picture below.
so the playground is really just 3 rectangles and one triangle, now the triangle has a base of 8 and a height of 6. We can simply get the area of each figure, sum them up and that's the area of the playground.

To get the answer we can use proportion.
30----------100%
12-----------x
Cross multiply now
30x=12*100%
30x=1200% /:30 (divide both sides by 30)
x=40% - it's the percentage of cars which finished the race.
100%-40%=60% - it's the answer