Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
Find the formula for an exponential function that passes through the two points given. Please show work. (-1,3/4) and (3,192)?
3 Answers
- 冷眼旁觀Lv 72 years agoFavorite Answer
The exponential function is: y = abˣ
where b > 0
When x = -1, y = 3/4:
3/4 = ab⁻¹
ab⁻¹ = 3/4 …… [1]
When x = 3, y = 192:
192 = ab³
ab³ = 192 …… [2]
[2]/[1]: b⁴ = 256
b = 4
Substitute b = 4 into [2]:
a * 4³ = 192
64a = 192
a= 3
The exponential function is: y = 3 * 4ˣ
- Anonymous1 year ago
I don't know.................
- billrussell42Lv 72 years ago
you have only 2 points, so there are an infinite number of solutions, and a straight line or other curves also are solutions.
try y = Ax² + B
plug in the numbers, solve for A and B
y = Ax² + B
3/4 = A + B
192 = 9A + B
subtract
191.25 = 8A
A = 23.90625
B = 0.75–23.90625 = –23.15625
so equation is
y = 23.90625 x² – 23.15625
check
x = –1
y = 0.75
x = 3
y = 192