When dividing exponential expressions with the same base, the quotient rule of exponents allows us to simplify by subtracting the exponents. For example, dividing \$4^3\( by \)4^1\( can be understood by expanding both terms: \)4^3\( is \)4 \times 4 \times 4\(, and \)4^1\( is simply \)4\(. Canceling one \)4\( from the numerator and denominator leaves \)4 \times 4\(, which is \)4^2\(. This matches the result of subtracting the exponents: \)3 - 1 = 2\(. Thus, the quotient rule states that for any nonzero base \)a\(,
\[\frac{a^m}{a^n} = a^{m-n}\]
where \)m\( and \)n\( are integers, and \)a \neq 0\(. This rule is intuitive when considering the division and subtraction symbols both involve a bar, linking the operation of division with subtracting exponents. Conversely, when multiplying exponential expressions with the same base, the exponents are added.
Applying this rule to variables, if we have \)y^7\( divided by \)y^5\(, the expression simplifies to \)y^{7-5} = y^2\(. Similarly, dividing \)m^6\( by \)m^6\( results in \)m^{6-6} = m^0$. This introduces the important zero exponent rule, which states that any nonzero number raised to the zero power equals one:
\[a^0 = 1 \quad \text{for} \quad a \neq 0\]
This can be verified by expanding both numerator and denominator and canceling identical factors, leaving the value 1. Understanding these exponent rules is essential for simplifying expressions efficiently and forms a foundation for more advanced algebraic manipulations.