Polynomial Operations: Complete Guide with 8 Worked Examples

Master SAT polynomial operations with this comprehensive guide. Learn addition, subtraction, multiplication (FOIL, special products), and division with 8 fully worked examples and expert strategies.

SAT Math – Advanced Math

Operations with Polynomials

Adding, subtracting, multiplying, and dividing polynomial expressions

Polynomial operations are the fundamental algebraic manipulations that extend arithmetic to expressions with variables. On the SAT, you'll add, subtract, multiply, and divide polynomials, apply special product formulas, and simplify complex expressions—skills essential for advanced algebra, calculus, and mathematical modeling.

Success requires understanding like terms, applying the distributive property systematically, recognizing special product patterns (difference of squares, perfect square trinomials), and organizing polynomial division. These operations aren't just algebraic exercises—they're the foundation for analyzing functions, solving equations, and modeling everything from projectile motion to economic relationships.

Understanding Polynomial Operations

What is a Polynomial?

A polynomial is an expression with variables raised to whole number exponents, combined with coefficients.

Example: \(3x^2 - 5x + 7\)
Terms: Parts separated by + or - signs
Coefficients: Numbers multiplying variables (3, -5, 7)
Degree: Highest exponent (2 in this example)

Like Terms

Like terms have the same variables with the same exponents.

Like terms: \(3x^2\) and \(7x^2\) can be combined
Unlike terms: \(3x^2\) and \(7x\) cannot be combined
Rule: Only like terms can be added/subtracted
Combine: Add or subtract coefficients, keep variable part

Special Products

Recognize patterns for faster multiplication.

Difference of squares: \((a+b)(a-b) = a^2 - b^2\)
Perfect square: \((a+b)^2 = a^2 + 2ab + b^2\)
Perfect square: \((a-b)^2 = a^2 - 2ab + b^2\)
Sum/diff of cubes: Special formulas (less common on SAT)

Distributive Property

The foundation of polynomial multiplication.

Basic: \(a(b + c) = ab + ac\)
FOIL: \((a+b)(c+d) = ac + ad + bc + bd\)
General: Multiply each term in first by each term in second
Combine: Simplify by combining like terms

Essential Formulas and Rules

Adding and Subtracting Polynomials

1. Remove parentheses (distribute negative sign if subtracting)

2. Identify like terms

3. Combine coefficients of like terms

4. Write result in standard form (descending exponents)

FOIL Method (Binomial × Binomial)

\((a + b)(c + d) = ac + ad + bc + bd\)

First: Multiply first terms

Outer: Multiply outer terms

Inner: Multiply inner terms

Last: Multiply last terms

Special Product Formulas

\((a + b)^2 = a^2 + 2ab + b^2\)

\((a - b)^2 = a^2 - 2ab + b^2\)

\((a + b)(a - b) = a^2 - b^2\)

Polynomial Long Division

1. Divide leading term of dividend by leading term of divisor

2. Multiply entire divisor by quotient term

3. Subtract from dividend

4. Repeat with new dividend until degree is less than divisor

Common Pitfalls & Expert Tips

❌ Sign errors when distributing negatives

When subtracting, distribute the negative to ALL terms: \((3x - 5) - (2x + 4) = 3x - 5 - 2x - 4\), not \(3x - 5 - 2x + 4\)!

❌ Forgetting middle term in perfect squares

\((x + 3)^2 = x^2 + 6x + 9\), NOT \(x^2 + 9\). The middle term \(2ab\) is crucial!

❌ Combining unlike terms

\(3x^2 + 5x\) cannot be combined into \(8x^2\) or \(8x\). Different exponents = unlike terms!

❌ Missing terms in multiplication

When multiplying polynomials, must multiply EVERY term in first by EVERY term in second. Don't skip combinations!

✓ Expert Tip: Organize vertically for complex problems

When adding/subtracting, align like terms vertically. This prevents errors and makes combining terms systematic.

✓ Expert Tip: Check by substitution

Verify multiplication by substituting a simple value like x = 2. Both original and expanded form should give same result.

✓ Expert Tip: Recognize special products instantly

\((x + 5)(x - 5)\) immediately becomes \(x^2 - 25\). No FOIL needed when you spot the pattern!

Fully Worked SAT-Style Examples

Example 1: Adding Polynomials

Simplify: \((3x^2 + 5x - 7) + (2x^2 - 3x + 4)\)

Solution:

Step 1: Remove parentheses

\(3x^2 + 5x - 7 + 2x^2 - 3x + 4\)

Step 2: Group like terms

\((3x^2 + 2x^2) + (5x - 3x) + (-7 + 4)\)

Step 3: Combine coefficients

\(5x^2 + 2x - 3\)

Answer: \(5x^2 + 2x - 3\)

Example 2: Subtracting Polynomials

Simplify: \((4x^2 - 6x + 9) - (2x^2 + 3x - 5)\)

Solution:

Step 1: Distribute negative sign to all terms in second polynomial

\(4x^2 - 6x + 9 - 2x^2 - 3x + 5\)

Step 2: Group like terms

\((4x^2 - 2x^2) + (-6x - 3x) + (9 + 5)\)

Step 3: Combine

\(2x^2 - 9x + 14\)

Key Point:

Negative sign changes ALL signs in second polynomial

+3x becomes -3x, -5 becomes +5

Answer: \(2x^2 - 9x + 14\)

Example 3: FOIL Method

Multiply: \((2x + 3)(x - 5)\)

Solution:

Apply FOIL:

First: \(2x \cdot x = 2x^2\)

Outer: \(2x \cdot (-5) = -10x\)

Inner: \(3 \cdot x = 3x\)

Last: \(3 \cdot (-5) = -15\)

Combine all terms:

\(2x^2 - 10x + 3x - 15\)

Combine like terms:

\(2x^2 - 7x - 15\)

Answer: \(2x^2 - 7x - 15\)

Example 4: Difference of Squares

Multiply: \((3x + 7)(3x - 7)\)

Solution:

Recognize pattern:

Form: \((a + b)(a - b)\)

This is difference of squares pattern!

Apply formula:

\((a + b)(a - b) = a^2 - b^2\)

Here: \(a = 3x\), \(b = 7\)

\((3x)^2 - 7^2 = 9x^2 - 49\)

Verify with FOIL:

\(9x^2 - 21x + 21x - 49 = 9x^2 - 49\) ✓

Middle terms cancel! Pattern recognition saves time.

Answer: \(9x^2 - 49\)

Example 5: Perfect Square Trinomial

Expand: \((2x - 5)^2\)

Solution:

Recognize pattern:

\((a - b)^2 = a^2 - 2ab + b^2\)

Here: \(a = 2x\), \(b = 5\)

Apply formula:

\(a^2 = (2x)^2 = 4x^2\)

\(-2ab = -2(2x)(5) = -20x\)

\(b^2 = 5^2 = 25\)

Combine:

\(4x^2 - 20x + 25\)

Answer: \(4x^2 - 20x + 25\)

Example 6: Multiplying with Distribution

Multiply: \(3x(2x^2 - 5x + 4)\)

Solution:

Distribute 3x to each term:

\(3x \cdot 2x^2 = 6x^3\)

\(3x \cdot (-5x) = -15x^2\)

\(3x \cdot 4 = 12x\)

Combine all products:

\(6x^3 - 15x^2 + 12x\)

Answer: \(6x^3 - 15x^2 + 12x\)

Example 7: Multiplying Three Terms

Multiply: \((x + 2)(x - 3)(x + 1)\)

Solution:

Step 1: Multiply first two binomials

\((x + 2)(x - 3) = x^2 - 3x + 2x - 6 = x^2 - x - 6\)

Step 2: Multiply result by third binomial

\((x^2 - x - 6)(x + 1)\)

Distribute each term:

\(x^2 \cdot x + x^2 \cdot 1 - x \cdot x - x \cdot 1 - 6 \cdot x - 6 \cdot 1\)

\(= x^3 + x^2 - x^2 - x - 6x - 6\)

Step 3: Combine like terms

\(x^3 + 0x^2 - 7x - 6 = x^3 - 7x - 6\)

Answer: \(x^3 - 7x - 6\)

Example 8: Combined Operations

Simplify: \(2(x + 3)^2 - (x - 1)(x + 4)\)

Solution:

Step 1: Expand \((x + 3)^2\)

\((x + 3)^2 = x^2 + 6x + 9\)

\(2(x^2 + 6x + 9) = 2x^2 + 12x + 18\)

Step 2: Expand \((x - 1)(x + 4)\)

\(x^2 + 4x - x - 4 = x^2 + 3x - 4\)

Step 3: Subtract (distribute negative)

\(2x^2 + 12x + 18 - (x^2 + 3x - 4)\)

\(= 2x^2 + 12x + 18 - x^2 - 3x + 4\)

Step 4: Combine like terms

\(x^2 + 9x + 22\)

Answer: \(x^2 + 9x + 22\)

Special Products Quick Reference

\((a + b)^2 = a^2 + 2ab + b^2\)

\((a - b)^2 = a^2 - 2ab + b^2\)

\((a + b)(a - b) = a^2 - b^2\)

Polynomial Operations: Building Algebraic Fluency

Mastering polynomial operations transforms algebra from memorized procedures into fluent mathematical thinking. Every time you add like terms, distribute correctly, or recognize a special product pattern, you're developing the algebraic intuition that distinguishes strong mathematics students. The SAT tests these skills because they're foundational for all higher mathematics—calculus begins with polynomial differentiation, linear algebra manipulates polynomial equations, and advanced functions are often approximated by polynomials. Beyond academics, polynomial operations model real-world relationships: the area of combined regions (adding polynomials), revenue functions (multiplying price by quantity polynomials), profit margins (subtracting cost from revenue), and countless optimization problems. Master the systematic approach: organize your work vertically, distribute carefully maintaining sign integrity, combine like terms methodically, and verify results. Recognize special products instantly to save time—when you see \((x+5)^2\), your brain should immediately produce \(x^2 + 10x + 25\) without FOIL. This fluency, built through practice and pattern recognition, is what enables you to focus on problem-solving rather than mechanical calculations when facing complex SAT questions or advanced mathematical challenges.