Math Problem Statement

Question 17 Write an exponential function for a graph that passes through the points (2, 336) and (3, 2688) . Write the function in the form y=a(b)x.

Solution

We are given two points: (2,336)(2, 336) and (3,2688)(3, 2688), and we need to find an exponential function of the form:

y=abxy = a \cdot b^x

Step 1: Use the points to form a system of equations

From the general form y=abxy = a \cdot b^x, we can substitute the given points into this equation to form two equations.

  1. For the point (2,336)(2, 336): 336=ab2336 = a \cdot b^2

  2. For the point (3,2688)(3, 2688): 2688=ab32688 = a \cdot b^3

Step 2: Solve the system of equations

Now, we can solve this system of equations.

Divide the second equation by the first to eliminate aa:

2688336=ab3ab2\frac{2688}{336} = \frac{a \cdot b^3}{a \cdot b^2}

Simplifying: 8=b8 = b

So, b=8b = 8.

Step 3: Solve for aa

Now that we know b=8b = 8, substitute this value back into one of the original equations. Let's use 336=ab2336 = a \cdot b^2 (from point (2,336)(2, 336)):

336=a82336 = a \cdot 8^2 336=a64336 = a \cdot 64

Solving for aa: a=33664=5.25a = \frac{336}{64} = 5.25

Step 4: Write the final equation

Now that we have a=5.25a = 5.25 and b=8b = 8, the exponential function is:

y=5.258xy = 5.25 \cdot 8^x


Do you need further clarification or have any questions about this process?

Here are some related questions:

  1. How do exponential growth and decay models differ?
  2. How would the equation change if the base bb were a fraction?
  3. What is the interpretation of the constant aa in this exponential function?
  4. How can we model a real-world situation with this exponential function?
  5. How can we find the value of the function at another point, say x=4x = 4?

Tip: In exponential functions, the base bb determines how quickly the function grows or decays. If b>1b > 1, the function grows exponentially.

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Math Problem Analysis

Mathematical Concepts

Exponential Functions
Systems of Equations
Algebra

Formulas

y = a * b^x

Theorems

Exponentiation properties
Solving systems of equations

Suitable Grade Level

Grades 9-11