Example

Multiplying (y7)(y+4)(y - 7)(y + 4) Using the FOIL Method

Multiply (y7)(y+4)(y - 7)(y + 4) using the FOIL method — the first binomial involves a subtraction, which introduces negative terms among the four FOIL products.

Step 1 — First: Multiply the first terms: yy=y2y \cdot y = y^2.

Step 2 — Outer: Multiply the outermost terms: y4=4yy \cdot 4 = 4y.

Step 3 — Inner: Multiply the innermost terms: (7)y=7y(-7) \cdot y = -7y.

Step 4 — Last: Multiply the last terms: (7)4=28(-7) \cdot 4 = -28.

Writing all four products in order gives:

y2+4y7y28y^2 + 4y - 7y - 28

Step 5 — Combine like terms: The Outer and Inner products 4y4y and 7y-7y are like terms with different signs: 4+(7)=34 + (-7) = -3:

y23y28y^2 - 3y - 28

The result is y23y28y^2 - 3y - 28. When one binomial contains a subtraction, the Inner and Last products involve multiplying by a negative number, so careful attention to sign rules is essential. Here, (7)y(-7) \cdot y produces the negative term 7y-7y, and (7)4(-7) \cdot 4 produces the negative constant 28-28.

Image 0

0

1

Updated 2026-04-29

Contributors are:

Who are from:

Tags

OpenStax

Elementary Algebra @ OpenStax

Ch.6 Polynomials - Elementary Algebra @ OpenStax

Algebra

Math

Prealgebra

Intermediate Algebra @ OpenStax

Ch.5 Polynomials and Polynomial Functions - Intermediate Algebra @ OpenStax

Related
Learn After