Answer:
Constant of proportionality is 12
The cost of buying new bicycle changes 12 dollar per week
Step-by-step explanation:
we are given
The equation as

where
d represents the amount in dollars
w is number of weeks
now, we can compare it with

where
k is constant of proportionality
we can compare
and we get
k=12
So,
Constant of proportionality is 12
we can see that

So,
The cost of buying new bicycle changes 12 dollar per week
Answer: 5 seconds
<u>Step-by-step explanation:</u>
Maximum height is the y-value of the vertex. The number of seconds at maximum height is the x-value (aka axis of symmetry).
h(x) = -2x² + 20x + 48
a=-2 b=20 c=48
Axis of symmetry: x = 
= 
= 
= 5
The answer is (-21, 13) for The second endpoint.
Let's start by calling the known endpoint L and the unknown K. We'll call the midpoint M. In order to find this, we must first note that to find a midpoint we need to take the average of the endpoints. To do this we add them together and then divide by 2. So, using that, we can write a formula and solve for each part of the k coordinates. We'll start with just x values.
(Kx + Lx)/2 = Mx
(Kx + 1)/2 = -10
Kx + 1 = -20
Kx = -21
And now we do the same thing for y values
(Ky + Ly)/2 = My
(Ky + 7)/2 = 10
Ky + 7 = 20
Ky = 13
This gives us the final point of (-21, 13)