(x-8)(x+8)

2 min read Jun 17, 2024
(x-8)(x+8)

Expanding the Expression (x-8)(x+8)

This expression represents the product of two binomials: (x-8) and (x+8). To expand it, we can use the FOIL method, which stands for:

  • First: Multiply the first terms of each binomial.
  • Outer: Multiply the outer terms of the binomials.
  • Inner: Multiply the inner terms of the binomials.
  • Last: Multiply the last terms of each binomial.

Let's apply FOIL to our expression:

F: x * x = x² O: x * 8 = 8x I: -8 * x = -8x L: -8 * 8 = -64

Now, combine the terms: x² + 8x - 8x - 64

Notice that the middle terms, +8x and -8x, cancel each other out. This leaves us with:

x² - 64

This is the expanded form of (x-8)(x+8).

Key Observation:

The expression (x-8)(x+8) is a special case known as the difference of squares. This pattern is evident in the result:

  • is the square of the first term (x).
  • 64 is the square of the second term (8).
  • The expression is a difference (subtraction) between these squares.

The general form of the difference of squares is:

(a - b)(a + b) = a² - b²

This pattern is very useful for factoring and simplifying expressions.

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