Skip to content
Mathematics

Exponential and logarithmic equations

Solve b^(a·x+c)=d or log_b(a·x+c)=d using your coefficients, with checks on the domain conditions.

Free & no registration Calculated in your browser
01

Your inputs

The starting values are an example.

Positive and different from 1.
Must not be zero.

Decimals: 12.5 · Thousands: 1,234.56. Follow the field instructions for lists.

02

Your result

Enter your values and select Calculate.

Your calculation will appear here.

Your result will include the relevant values and units.

Understand the calculation

Formula and example

How it is calculated

b^(ax+c)=d: x=[ln(d)/ln(b)−c]/a. log_b(ax+c)=d: x=(b^d−c)/a.

Worked example

2^x=8 gives x=3. For log₂(2x+1)=3, we obtain 2x+1=8 and therefore x=3.5.

Things to check

  • The base must be positive and different from 1. For the exponential equation, d must be positive.
  • This calculator handles the two stated basic forms, rather than arbitrary mixed equations.

Frequently asked questions

Are bases between 0 and 1 allowed?

Yes. The logarithm is then decreasing, but the transformations remain valid as long as all domain conditions are met.