Question

Solving Exponential Equations with Unequal Bases
Problem:
3^(x-4)=7^(x+9)
Answer Options:
x ≈ –25.86

x ≈ –0.04

x ≈ –0.39

x ≈ –2.59

Answer 1

take log on both sides
\( \ln3^{x-4} = \ln{7^{x+9}}\)
\( = (x-4)\ln 3 = (x+9)\ln7\) <--- solve this equation.

Answer 2

i dont know how to solve it, i have no idea how to work these problems.

Answer 3

use calculator to calculate the value of log.
http://www.wolframalpha.com/input/?i=solve+%28x%E2%88%924%29ln3%3D%28x%2B9%29ln7