An exponential equation is one where a variable appears in the exponent. To solve exponential equations without logarithms, both sides must have comparable exponential expressions with the same base, so the powers can be set equal. If both sides can be expressed as powers of the same base b, the property b^x = b^y implies x = y can be used to set the exponents equal and solve for the variable. This demonstrates how exponential equations are solved by setting the powers equal when the bases are the same. For equations that cannot be expressed with a common base, logarithms are used.