Multiplying a monomial by a trinomial

8.4.2 Multiplying a monomial by a trinomial

Description

Quick Overview

In this section, we learn to multiply a monomial by a trinomial using the distributive law, simplifying the process by breaking it down into manageable parts.

Standard

The section provides a clear explanation of how to multiply a monomial by a trinomial using the distributive law, demonstrating the process through various examples and emphasizing the significance of each term's multiplication and simplification.

Detailed

Multiplying a Monomial by a Trinomial

In algebra, multiplication involves not only multiplying numbers but also extending the method to algebraic expressions. A monomial is an expression containing a single term, while a trinomial contains three terms.

To multiply a monomial by a trinomial, we utilize the distributive law, which allows us to multiply each term in the trinomial by the monomial separately. For example, if we take a monomial such as 3p and multiply it by the trinomial 4p² + 5p + 7, we can break this down into:

$$
3p \times (4p² + 5p + 7) = (3p \times 4p²) + (3p \times 5p) + (3p \times 7)
$$

This results in:

  • 12p³ from multiplying 3p and 4p²
  • 15p² from multiplying 3p and 5p
  • 21p from multiplying 3p and 7

The final outcome of this multiplication yields a polynomial: 12p³ + 15p² + 21p. This systematic approach not only simplifies the process of multiplying complex expressions but also sets the foundation for polynomial algebra, making further expressions easier to handle. In summary, mastering this technique is vital for solving more advanced algebraic expressions.

Key Concepts

  • Distributive Law: The technique used to multiply each term in a polynomial by a monomial.

  • Simplifying Expression: The process of combining like terms to present the multiplication result in a simplified format.

  • Term-by-Term Multiplication: The method of multiplying each term of a trinomial by a monomial to obtain the final polynomial.

Memory Aids

🎵 Rhymes Time

  • When multiplying, take a cue, Distribute first, it's easy to do!

📖 Fascinating Stories

  • Imagine a shop where a single item price is multiplied by several customers’ carts—a clear view of distribution!

🧠 Other Memory Gems

  • 'DPA' stands for Distribute, Product, Add—keep multiplying until you’re glad!

🎯 Super Acronyms

DPA = Distribute, then Product, and finally Add.

Examples

  • Multiply 3p by 4p² + 5p + 7: Result is 12p³ + 15p² + 21p.

  • Multiply x by 2x² + 3x + 5: Result is 2x³ + 3x² + 5x.

Glossary of Terms

  • Term: Monomial

    Definition:

    An algebraic expression that contains only one term.

  • Term: Trinomial

    Definition:

    An algebraic expression that consists of three terms.

  • Term: Distributive Law

    Definition:

    A property of multiplication over addition or subtraction, allowing the multiplication of a single term by each term in a sum or difference.

  • Term: Polynomial

    Definition:

    An algebraic expression formed from one or more monomials.