The formula y equals 15 left parenthesis 1.26 right parenthesis to the power of x gives the number of cellular phone users y (in
1 answer:
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Answer:
Step-by-step explanation:
(2):
First let's organise the data:
33 miles ... x mph ... 4h - downstream
33 miles ... y mph ... 7h - up the stream
x = 33/4 = 8.25 mph
y = 33/7 = 4.71 mph
(3)
P(x) =
To find the amount of key rings sold when the profit is 5000$ we have to equate P(x) with 5, because in the problem the profit of the key rings is displayed in terms of thousands.
Since the number of keyrings sold has to be positive the only answer is 4 thousand key rings.
Answer:
see explanation
Step-by-step explanation:
The equation of a parabola in vertex form is
y = a(x - h)² + k
where (h, k) are the coordinates of the vertex and a is a multiplier
here (h, k) = (- 3, - 14), thus
y = a(x + 3)² - 14
To find a substitute (0, - 13) into the equation
- 13 = 9a - 14 ( add 14 to both sides )
9a = 1 ( divide both sides by 9 )
a = , hence
y = (x + 3)² - 14 ← equation of parabola
To find the x- intercepts let y = 0
(x + 3)² - 14 = 0
Multiply through by 9
(x + 3)² - 126 = 0 ( add 126 to both sides )
(x + 3)² = 126 ( take the square root of both sides )
x + 3 = ± = ± 3
Subtract 3 from both sides
x = - 3 ± 3
The x- intercepts are therefore
x = - 3 - 3 ≈ - 14.22 ( to 2 dec. places ) or
x = - 3 + 3 ≈ 8.22 ( to 2 dec. places )