### Home > A2C > Chapter 13 > Lesson 13.1.1 > Problem13-6

13-6.

Factor each of the following expressions.

1. $x^2 - 4$

Remember that a difference of two squares has a special factoring pattern.
$a² - b² = (a - b)(a + b)$

$(x + 2)(x - 2)$

1. $y^2 - 81$

Use the same method as part (a).

1. $1 - x^2$

This might look different than the expressions in parts (a) and (b), but you can use the same method to factor it.

$(1 - x)(1 + x)$

1. $1 -$ sin2$(x)$

Think of sin² ($x$) as one big variable (like $x²$).
Then use the same method as part (c) to factor it.