Math Problem Statement

Find the x-intercept of the exponential function h(x)=5^x-12 with a horizontal asymptote y=-1

Solution

To find the xx-intercept of the function h(x)=5x12h(x) = 5^x - 12 with a horizontal asymptote y=1y = -1, follow these steps:

Step 1: Set the function equal to 0

The xx-intercept occurs when h(x)=0h(x) = 0, so set the equation equal to 0: 0=5x120 = 5^x - 12

Step 2: Solve for 5x5^x

Add 12 to both sides to isolate the exponential term: 5x=125^x = 12

Step 3: Take the logarithm of both sides

To solve for xx, take the natural logarithm (or any logarithm) of both sides: ln(5x)=ln(12)\ln(5^x) = \ln(12)

Step 4: Apply the logarithmic property

Use the logarithmic property ln(ab)=bln(a)\ln(a^b) = b \ln(a) to simplify: xln(5)=ln(12)x \ln(5) = \ln(12)

Step 5: Solve for xx

Now divide both sides by ln(5)\ln(5): x=ln(12)ln(5)x = \frac{\ln(12)}{\ln(5)}

Step 6: Approximate the value of xx

Using a calculator: x2.48491.60941.544x \approx \frac{2.4849}{1.6094} \approx 1.544

Thus, the xx-intercept is approximately x1.544x \approx 1.544.

Would you like more details or have any further questions?

Here are 5 related questions:

  1. What is the general form of an exponential function?
  2. How do you determine the horizontal asymptote of an exponential function?
  3. What are the properties of logarithmic functions?
  4. How do you find the derivative of 5x5^x?
  5. How do logarithms simplify the solving of exponential equations?

Tip: The horizontal asymptote helps to determine the long-term behavior of an exponential function.

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Math Problem Analysis

Mathematical Concepts

Exponential Functions
Logarithms
Algebra

Formulas

Exponential Function: h(x) = 5^x - 12
Logarithmic Property: ln(a^b) = b * ln(a)

Theorems

Logarithmic Function Theorem

Suitable Grade Level

Grades 9-12