Answer:
12 degrees.
Step-by-step explanation:
8 - (-4) = 12. So, the temperature increased by 12 degrees.
Answer:
There is 7.5% increase in the number of songs on his mp3 player.
Step-by-step explanation:
Original Songs in mp3= 440 songs
Final Songs in mp3= 473 songs
We need to find percent of increase in the number of songs on his mp3 player.
The formula used is: 
Now putting values and finding percent of increase
So, there is 7.5% increase in the number of songs on his mp3 player.
Answer: f(x) = -0.016x² + 1.6x
Step-by-step explanation:
If the lenght of the road over the arch is 100m, we can consider a coordinate plane and say that the road starts at point (0,0) and finishes at (100,0). The vertice of the parabola is at point (50,40), because the maximum height is 40 and it is always in the middle point of the roots.
So, we have
(0,0) (50,40) (100,0)
A quadratic function is always on the form: f(x) = ax² + bx + c
0 = a0² + b0 + c
40 = a50² + b50 + c
0 = a100² + b100 + c
0 = a0² + b0 + c → c = 0 ∴
40 = a50² + b50
0 = a100² + b100
_________________________
2500a + 50b = 40 (*2)
10000a + 100b = 0
_________________________
5000a + 100b = 80
10000a + 100b = 0 (-)
__________________________
-5000a = 80
-a=80/5000
a=-0.016
∴
2500a + 50b = 40
2500.(-0.016) + 50b = 40
-40 + 50b = 40
50b = 80
b = 80/50
b = 1.6
This way f(x) = -0.016x² + 1.6x
