Step 1: Model x² − 9 by placing tiles in the Product section. (Do not try to form a rectangle.)

Step 2: Form a rectangle of tiles in the product section. Add as many zero-pair tiles as necessary.

Step 3: Drag tiles to the sections labeled Factor 1 and Factor 2 to represent the factors.

Step 4: What is the factored form of this trinomial?
 (x − 1) (x + 9)
 (x − 3) (x − 3)
 (x − 3) (x + 3)
 (x − 9) (x + 1)