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If f(x) is an exponential function where f(-0.5) = 28 and f(8.5) = 88, then find the value of f(1.5), to the nearest hundredth.

User Iopq
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2 Answers

3 votes

Final answer:

To find the value of f(1.5) for an exponential function, we can use given points to form the equation and solve for the unknown variables. Then, substitute the value of x = 1.5 into the equation to calculate f(1.5).

Step-by-step explanation:

To find the value of f(1.5), we need to determine the equation of the exponential function. We already have two points on the graph: f(-0.5) = 28 and f(8.5) = 88. Using these points, we can form the equation
f(x) = a * b^x, where a is the initial value of the function and b is the growth factor.

Using the point (-0.5, 28), we substitute these values into the equation to solve for a:


28 = a * b^{(-0.5)

Next, using the point (8.5, 88), we substitute these values into the equation:


88 = a * b^{(8.5)

Solving these two equations simultaneously will give us the values of a and b. Once we have these values, we can calculate f(1.5) by plugging x = 1.5 into the equation
f(x) = a * b^x.

User ImFarhad
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The exponential function is
\text{f(x)} = 30 * 1.14^x and the value of f(1.5) is 36.5

How to determine the exponential function

From the question, we have the following parameters that can be used in our computation:

f(-0.5) = 28

f(8.5) = 88

An exponential function is represented as


\text{f(x)} = ab^x

Using the points, we have


ab^(-0.5) = 28


ab^(8.5) = 88

Divide the functions

So, we have


(ab^(8.5))/(ab^(-0.5)) = (88)/(28)

Evaluate


b^9 = 3.143

Take the 9th root of both sides

b = 1.14

Recall that


ab^(-0.5) = 28

So, we have


a * 1.14^(-0.5) = 28

a * 0.94 = 28

Divide

a = 30

This means that


\text{f(x)} = 30 * 1.14^x

When x = 1.5, we have


\text{f(1.5)} = 30 * 1.14^{1.5

Evaluate


\text{f(1.5)} = 36.5

Hence, the exponential function is
\text{f(x)} = 30 * 1.14^x and the value of f(1.5) is 36.5

User Michael Ruhnau
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