Math Problem Statement

Negative exponents and factoring

Solution

Negative exponents and factoring are two distinct but important concepts in algebra. Let's break them down separately:

1. Negative Exponents

A negative exponent indicates the reciprocal of the base raised to the opposite positive exponent. The general rule is:

an=1ana^{-n} = \frac{1}{a^n}

For example:

  • 23=123=182^{-3} = \frac{1}{2^3} = \frac{1}{8}
  • x2=1x2x^{-2} = \frac{1}{x^2}

In expressions involving negative exponents, the goal is often to rewrite the expression with only positive exponents.

Example:

Simplify x3y2z1\frac{x^{-3}y^2}{z^{-1}}: x3y2z1=y2x3z=zy2x3\frac{x^{-3}y^2}{z^{-1}} = \frac{y^2}{x^3} \cdot z = \frac{zy^2}{x^3} Notice how negative exponents were moved to the other side of the fraction, changing the signs of the exponents.

2. Factoring

Factoring is the process of breaking down an expression into a product of simpler expressions (or factors). It’s often used to simplify equations or expressions, making them easier to solve.

Common Factoring Techniques:

  • Factoring out the Greatest Common Factor (GCF): For example, in 6x2+9x6x^2 + 9x, the GCF is 3x, so: 6x2+9x=3x(2x+3)6x^2 + 9x = 3x(2x + 3)

  • Factoring Quadratic Trinomials: For example, x2+5x+6x^2 + 5x + 6 can be factored as: (x+2)(x+3)(x + 2)(x + 3)

  • Difference of Squares: For example, a2b2a^2 - b^2 factors into: (ab)(a+b)(a - b)(a + b)

Example of Combining Both:

If you are asked to simplify x2+2x1+1x^{-2} + 2x^{-1} + 1, first rewrite it with positive exponents: 1x2+2x+1\frac{1}{x^2} + \frac{2}{x} + 1 Multiply the entire expression by x2x^2 to clear the fractions: 1+2x+x21 + 2x + x^2 Now, factor the quadratic: (x+1)(x+1)=(x+1)2(x + 1)(x + 1) = (x + 1)^2

Summary

  • Negative exponents indicate reciprocals.
  • Factoring is breaking down expressions into products of simpler factors.

Want more details or have any questions?

Here are some related questions to explore further:

  1. How do you simplify more complex expressions involving multiple negative exponents?
  2. What are some tips for factoring polynomials with four or more terms?
  3. How does factoring help in solving quadratic equations?
  4. Can you explain how negative exponents work in the context of scientific notation?
  5. How do you factor higher-degree polynomials like x3+3x2+3x+1x^3 + 3x^2 + 3x + 1?

Tip: Always check if you can factor an expression before trying other methods of solving! Factoring simplifies many problems.

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Math Problem Analysis

Mathematical Concepts

Negative Exponents
Factoring
Reciprocal Rules
Polynomial Simplification

Formulas

a^{-n} = \frac{1}{a^n}
a^2 - b^2 = (a - b)(a + b)

Theorems

Negative Exponent Rule
Difference of Squares
Factoring Trinomials

Suitable Grade Level

Grades 9-11