Problem 12 - Algebra 2

Question

Factor each expression. $$ x^{2}+22 x+40 $$

Step-by-Step Solution

Answer

\((x + 2)(x + 20)\)

Step 1: Determine the product and sum

To factor the quadratic expression of the form \(x^2 + bx + c\), we need two numbers that multiply to \(c\) (40 in this case) and add up to \(b\) (22 in this case).

Step 2: Find the pair of factors

Find two numbers that multiply to 40 and add up to 22. After evaluating possible pairs, we determine that 2 and 20 meet both criteria.

Step 3: Write the expression as a product of binomials

Now that we have the pair of numbers, the quadratic expression can be rewritten as \((x + 2)(x + 20)\). This gives the factored form of the expression.

Key Concepts

Quadratic Equations

Quadratic equations represent relationships where a variable is squared, typically taking the general form of (ax^2 + bx + c = 0), where (a, b, and c) are constant numbers with (a eq 0).

In the context of the provided exercise, the quadratic expression is (x^2 + 22x + 40), a simplified version where the coefficient of (x^2) is 1 (often called a monic quadratic).

To solve such an equation, or to factor the expression, we look for two numbers that can both add to the coefficient of (x), here 22, and multiply to the constant term, here 40.

With a foundational understanding of how these numbers interact, one can grasp the underpinnings of quadratic equations and efficiently navigate towards the solutions.

Binomials

Binomials are algebraic expressions containing two unlike terms, for example, (x + y). They are the cornerstone blocks for higher-order polynomials. In factoring, our goal is often to break down complex expressions into products of simpler binomial factors.

When factoring quadratic expressions like (x^2 + 22x + 40), we essentially search for a pair of binomials that, when multiplied, yield the original expression. These binomials are often reflected in the factorized form, such as ((x + m)(x + n)), where m and n are the numbers found that meet the sum and product requirements.

Binomial factors can help in visualizing and solving quadratic equations by encapsulating the two roots or solutions of the equation, laying the groundwork for the quadratic formula and the factor theorem.

Polynomial Factorization

Polynomial factorization, or factoring, is the process of breaking down a polynomial into a product of its simplest components or factors.

For the quadratic expression (x^2 + 22x + 40), factoring involves finding a pair of binomials that multiply to give the original polynomial. It's akin to reverse-engineering the distributive property.

By identifying key numbers that align with the coefficients, students can transform seemingly complex expressions into manageable building blocks, enabling further algebraic manipulation, like solving equations or simplifying expressions.

Mastering polynomial factorization is a fundamental algebra skill that enriches a student's mathematical toolkit, preparing them for more advanced topics in calculus and beyond.