The fundamental laws of exponents form the cornerstone of algebraic operations in the set of real numbers (R). When multiplying powers with identical bases, we add the exponents [a^m * a^n = a^(m+n)]. Conversely, when dividing powers with like bases, we subtract the exponents [a^m / a^n = a^(m-n)]. Furthermore, any non-zero real number raised to the power of zero equals one [a^0 = 1, where a != 0]. A negative exponent denotes the multiplicative inverse (reciprocal) of the base [a^(-n) = 1 / a^n], allowing us to transform any negative power into a positive exponent by shifting it between the numerator and the denominator.
Quick Concept Check
Question: What is the result of multiplying and dividing like bases? What is the value of any non-zero number to power zero?
Key Answer: When multiplying like bases we add exponents, when dividing we subtract exponents, and any non-zero number to power zero equals 1.
The Power of a Power Law states that for any real base 'a' and any integers 'm' and 'k', raising a power to another exponent requires multiplying the inner and outer exponents: [(a^m)^k = a^(m * k)]. For example, (2^3)^2 = 2^(3 * 2) = 2^6 = 64. This principle applies equally to radical terms and rational numbers; for instance, [(sqrt(3))^2]^4 = (sqrt(3))^(2 * 4) = (sqrt(3))^8 = 3^4 = 81. Mastering this rule significantly simplifies complex radical and polynomial expressions.
Quick Concept Check
Question: State the algebraic formula for power of a power. Calculate [(sqrt(5))^2]^3.
Key Answer: Formula is (a^m)^k = a^(m * k). For [(sqrt(5))^2]^3 = (sqrt(5))^6 = 5^3 = 125.
Exponents distribute over multiplication and division, but never over addition or subtraction:
1. Power of a Product: [(a * b)^n = a^n * b^n], where the exponent applies to each factor inside the parentheses.
2. Power of a Quotient: [(a / b)^n = a^n / b^n], provided that b != 0.
3. Negative Power of a Fraction: [(a / b)^(-n) = (b / a)^n], which means inverting the fraction immediately converts a negative exponent into a positive one; e.g., (2/3)^(-2) = (3/2)^2 = 9/4.
Quick Concept Check
Question: Do exponents distribute over addition? How do we evaluate a fraction raised to a negative exponent?
Key Answer: Exponents never distribute over addition or subtraction. For a negative exponent on a fraction, invert numerator and denominator to make the power positive.
An exponential equation is an equation where the unknown variable (x) appears in the exponent position. They are resolved using two primary golden principles:
1. (If Bases are Equal, Exponents are Equal): If a^x = a^y and a not in {-1, 0, 1}, then x = y. Example: 2^(x + 1) = 8 = 2^3 => x + 1 = 3 => x = 2.
2. (If Exponents are Equal and Bases are Distinct): If a^x = b^x where |a| != |b|, then the exponent must equal zero [x = 0]. Example: 3^(x - 5) = 7^(x - 5) => x - 5 = 0 => x = 5.
Quick Concept Check
Question: Solve: 3^(x - 2) = 27, and solve: 5^(x + 4) = 9^(x + 4).
Key Answer: First: 3^(x-2) = 3^3 => x - 2 = 3 => x = 5. Second: Bases differ so exponent must be zero: x + 4 = 0 => x = -4.