How to Solve Exponential & Logarithmic Equations

To solve an exponential or logarithmic equation, change the given equation into one of the following forms, where a and b are real numbers, a > 0 and

 a ≠ 1, and follow the guidelines.

  1. af(x)=b
    Solve by taking the logarithm of both sides.
  2. logaf(x)=b
    Solve by changing to exponential form ab=f(x).
  3. logaf(x)=logag(x)
    The given equation is equivalent to the equation f(x)=g(x). Solve algebraically.
  4. In a more complicated equation, it may be necessary to first solve for af(x) or logaf(x)and then solve the resulting equation using the methods above.
  5. Check that each of the proposed solutions is in the domain.