Multiply \( (x+1)(x-1) \)

When you multiply \( (x+1)(x-1) \), you're essentially using the difference of squares formula, which states that \( (a+b)(a-b) = a^2 - b^2 \). Here, \( a = x \) and \( b = 1 \). So, you calculate it as follows: \[ (x+1)(x-1) = x^2 - 1^2 = x^2 - 1 \] And just like that, you've simplified the expression to \( x^2 - 1 \)! If you're ever in doubt about expanding binomials, remember the FOIL method. That’s First, Outside, Inside, Last! For this example, you’d take the First terms \( x \cdot x \), the Outside terms \( x \cdot (-1) \), the Inside terms \( 1 \cdot x \), and the Last terms \( 1 \cdot (-1) \). Tally up all those terms, and voilà – you’ll arrive at \( x^2 - 1 \) in no time.