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An exponential function, f(x), passes through (4,-2) and (5,10) and has a horizontal asymptote at y=-8. What is an equation of f(x) ?
f(x)=◻

An exponential function, f(x) f(x) , passes through (4,2) (4,-2) and (5,10) (5,10) and has a horizontal asymptote at y=8 y=-8 . What is an equation of f(x) f(x) ?\newlinef(x)=f(x)=\square

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Q. An exponential function, f(x) f(x) , passes through (4,2) (4,-2) and (5,10) (5,10) and has a horizontal asymptote at y=8 y=-8 . What is an equation of f(x) f(x) ?\newlinef(x)=f(x)=\square
  1. Identify Asymptote: An exponential function with a horizontal asymptote at y=8y = -8 can be written in the form f(x)=abx+cf(x) = a \cdot b^x + c, where cc is the horizontal asymptote. So, c=8c = -8.
  2. Find Values of a and b: We have: f(x)=abx8f(x) = a \cdot b^x - 8. Now we need to find the values of aa and bb using the points (4,2)(4, -2) and (5,10)(5, 10).
  3. Equation from Point (4,2)(4, -2): Using the point (4,2)(4, -2), we get the equation 2=ab48-2 = a \cdot b^4 - 8. Adding 88 to both sides gives us ab4=6a \cdot b^4 = 6.
  4. Equation from Point (5,10)(5, 10): Using the point (5,10)(5, 10), we get the equation 10=ab5810 = a \cdot b^5 - 8. Adding 88 to both sides gives us ab5=18a \cdot b^5 = 18.
  5. Eliminate aa to Solve for bb: Now we have two equations: ab4=6a \cdot b^4 = 6 and ab5=18a \cdot b^5 = 18. We can divide the second equation by the first to eliminate aa and solve for bb.\newlineab5ab4=186\frac{a \cdot b^5}{a \cdot b^4} = \frac{18}{6}\newlineb=3b = 3
  6. Substitute bb to Find aa: Now that we have bb, we can substitute it back into one of the equations to find aa. Using ab4=6a \cdot b^4 = 6 and b=3b = 3, we get:\newlinea34=6a \cdot 3^4 = 6\newlinea81=6a \cdot 81 = 6\newlinea=681a = \frac{6}{81}\newlinea=113.5a = \frac{1}{13.5}
  7. Final Exponential Function: Substituting a=113.5a = \frac{1}{13.5} and b=3b = 3 into f(x)=abx8f(x) = a \cdot b^x - 8 gives us the final equation f(x)=(113.5)3x8f(x) = \left(\frac{1}{13.5}\right) \cdot 3^x - 8.

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