Final answer:
The equivalent expression for am: an in mathematics is a to the power of (m-n) using the quotient rule of exponents which states that you subtract the exponents when dividing two expressions with the same base.
Step-by-step explanation:
In mathematics, the expression am: an represents the ratio of two exponential expressions with the same base 'a' raised to different exponents, 'm' and 'n' respectively. To simplify this expression, we use the quotient rule of exponents, which states that when you divide two exponents with the same base, you subtract the exponents. Applying this rule, the equivalent expression for am: an is am-n.