Carpeting costs $7.99 a yard. If Jan buys 12.4, how much will it cost?
2 answers:
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Answer:
- y = -2(x -3)² +24
- 16 feet
Step-by-step explanation:
We expect the equation for y to be quadratic. Since the table is obviously symmetrical about x=3, we can start with the vertex form ...
y = a(x -3)² +b
Filling in the values from the first two table points, we get
For (x, y) = (0, 6):
6 = a(0 -3)² + b ⇒ 9a +b = 6
For (x, y) = (2, 22):
22 = a(2-3)² +b ⇒ a +b = 22
Subtracting the second equation from the first gives ...
(9a +b) -(a +b) = (6) -(22)
8a = -16 . . . . . . collect terms
a = -2 . . . . . . . . divide by 8
The second equation above tells us ...
b = 22 -a = 22 -(-2) = 24
So, our equation for y is ...
y = -2(x -3)² +24
__
The value of y for x=5 is ...
y = -2(5 -3)² +24 = 16
The height of the ball after 5 seconds is 16 feet.
Given function :
We need to identify a " initial amount", b "growth factor", r " rate of growth".
We know, exponential growth formula
, where a is initial amount, b is growth factor. On comparing with given function let us find values of a and b.
⇔
.
We can see a= 1.05 and b = 1.46.
Now, b=1+r.
Therefore, 1+r =1.46.
Subtracting 1 from both sides, we get
1+r-1 =1.46-1
r = 0.46.
On converting 0.46 into percentage, we get
0.46 × 100 = 46.
Therefore, intial amount a = a= 1.05 , growth factor b = 1.46, and the rate of growth r= 46%.